feat: add Notion-style breadcrumb navigation with dropdown menus

Backend:
- Added _nav_breadcrumb() to build page hierarchy chain (root → current)
- New /api/nav/menu endpoint returns workspace/folder children with has_children flag
- view_page() and view_page_root() now pass breadcrumb_items, nav_workspace_id, nav_page_id to template

Header template (_header.html):
- Replaced static breadcrumb with Alpine.js fdBreadcrumb() component
- Breadcrumb items now clickable with dropdown menus showing

app/routers/board.py

@@ -965,10 +965,16 @@ async def view_page(request: Request, page_id: int):
         page_data["file_size"] = file_size
         page_data["file_name"] = filename
 
+    from app.routers.dashboard import _nav_breadcrumb
+    with get_conn() as conn:
+        nav_crumbs = _nav_breadcrumb(conn, page_id)
     ctx = {**sidebar, "page": page, "page_favorited": fav is not None,
            "page_share_mode": page.get("share_mode", "private"),
            "page_published": bool(page.get("published", 0)),
-           "page_data": page_data}
+           "page_data": page_data,
+           "breadcrumb_items": nav_crumbs,
+           "nav_workspace_id": page.get("workspace_id") or 0,
+           "nav_page_id": page_id}
     template = env.get_template("page_editor.html")
     response = template.render(**ctx)
     return HTMLResponse(content=response, headers={"Cache-Control": "no-store, max-age=0"})

app/routers/dashboard.py

@@ -264,11 +264,16 @@ async def view_page_root(request: Request, page_id: int):
         page_data["file_size"] = file_size
         page_data["file_name"] = filename
 
+    with get_conn() as conn:
+        nav_crumbs = _nav_breadcrumb(conn, page_id)
     ctx = {**sidebar, "page": page, "sub_pages": [dict(s) for s in subs],
            "page_favorited": fav is not None,
            "page_share_mode": page.get("share_mode", "private"),
            "page_published": bool(page.get("published", 0)),
-           "page_data": page_data}
+           "page_data": page_data,
+           "breadcrumb_items": nav_crumbs,
+           "nav_workspace_id": page.get("workspace_id") or 0,
+           "nav_page_id": page_id}
     template = env.get_template("page_editor.html")
     response = template.render(**ctx)
     return HTMLResponse(content=response, headers={"Cache-Control": "no-store, max-age=0"})
@@ -827,6 +832,99 @@ def _build_breadcrumb(conn, folder_id: int) -> list:
     return breadcrumb
 
 
+def _nav_breadcrumb(conn, page_id: int) -> list:
+    """Build a Notion-style breadcrumb chain (root -> page) for the header.
+
+    Returns a list of dicts: {id, label, url, icon, menu}. The last item is the
+    current page (url = None). Every item has ``menu: True`` so the header can
+    open a sibling-navigation dropdown for it.
+    """
+    from app.routers.board import _file_icon
+    chain = []
+    current = page_id
+    seen = set()
+    while current and current not in seen:
+        seen.add(current)
+        row = conn.execute(
+            "SELECT id, title, parent_id, parent_section, content_format "
+            "FROM pages WHERE id=? AND deleted_at IS NULL",
+            (current,),
+        ).fetchone()
+        if not row:
+            break
+        is_folder = row["parent_section"] == "Workspace"
+        title = row["title"] or "Untitled"
+        chain.insert(0, {
+            "id": row["id"],
+            "label": title,
+            "url": None,
+            "icon": "\U0001F4C1" if is_folder else _file_icon(title, row["content_format"]),
+            "menu": True,
+        })
+        current = row["parent_id"]
+    # All items except the current page are navigable links.
+    for i, item in enumerate(chain):
+        if i < len(chain) - 1:
+            item["url"] = f"/pages/{item['id']}"
+    return chain
+
+
+@router.get("/api/nav/menu")
+async def nav_menu(request: Request, workspace_id: int = None, parent_id: int = None):
+    """Return the pages at one level for the header breadcrumb navigation menu.
+
+    If ``parent_id`` is given, returns that page's children; otherwise the
+    workspace's root pages. Each item includes ``has_children`` so the frontend
+    can render an expandable sub-menu.
+    """
+    from app.routers.board import _file_icon
+    ws_id = workspace_id
+    if not ws_id:
+        ws = _get_active_workspace(request, user_id=_get_user_id(request))
+        ws_id = ws["id"] if ws else None
+    if not ws_id:
+        return {"items": []}
+    with get_conn() as conn:
+        if parent_id:
+            rows = conn.execute(
+                "SELECT id, title, parent_section, content_format FROM pages "
+                "WHERE parent_id=? AND workspace_id=? AND deleted_at IS NULL "
+                "ORDER BY sort_order ASC, created_at DESC",
+                (parent_id, ws_id),
+            ).fetchall()
+        else:
+            rows = conn.execute(
+                "SELECT id, title, parent_section, content_format FROM pages "
+                "WHERE parent_id IS NULL AND workspace_id=? AND deleted_at IS NULL "
+                "ORDER BY sort_order ASC, created_at DESC",
+                (ws_id,),
+            ).fetchall()
+        ids = [r["id"] for r in rows]
+        child_counts = {}
+        if ids:
+            placeholders = ",".join("?" for _ in ids)
+            cc_rows = conn.execute(
+                f"SELECT parent_id, COUNT(*) AS c FROM pages "
+                f"WHERE parent_id IN ({placeholders}) AND deleted_at IS NULL "
+                f"GROUP BY parent_id",
+                ids,
+            ).fetchall()
+            for cr in cc_rows:
+                child_counts[cr["parent_id"]] = cr["c"]
+        items = []
+        for r in rows:
+            is_folder = r["parent_section"] == "Workspace"
+            title = r["title"] or "Untitled"
+            items.append({
+                "id": r["id"],
+                "name": title,
+                "icon": "\U0001F4C1" if is_folder else _file_icon(title, r["content_format"]),
+                "has_children": child_counts.get(r["id"], 0) > 0,
+                "url": f"/pages/{r['id']}",
+            })
+    return {"items": items}
+
+
 @router.post("/api/local-workspace/items")
 async def create_local_workspace_item(request: Request):
     """Create a new file in the active workspace."""

app/templates/_header.html

@@ -1,11 +1,38 @@
-{# ── Unified Header (Notion-inspired) ──
+{# ── Unified Header (Notion-inspired breadcrumb navigation) ──
    Parameters available in calling context:
-     breadcrumb_items: list of {label: str, url: str|None} — last item = current page
+     breadcrumb_items: list of {label, url, id, icon, menu} — last item = current page
      page_icon: str — emoji icon
+     page_title: str — fallback current-page label when no breadcrumb_items
      right_actions: str — raw HTML for right-side action buttons
-     hamburger_click: str — Alpine expression for hamburger button (default: opens sidebar)
+     hamburger_click: str — Alpine expression for hamburger button
      hide_hamburger: bool — if truthy, hides the hamburger button
+     hide_home: bool — if truthy, do not prepend the "Home" crumb
+     nav_workspace_id: int — workspace id used to fetch the navigation menu
+     nav_page_id: int — current page id (enables the sibling nav menu)
 #}
+{% set ns = namespace(items=[]) %}
+{% if not hide_home %}
+  {% set ns.items = ns.items + [{"label": "Home", "url": "/workspaces", "id": none, "icon": "🏠", "menu": false, "home": true}] %}
+{% endif %}
+{% if breadcrumb_items %}
+  {% for item in breadcrumb_items %}
+    {% set ns.items = ns.items + [{
+        "label": item.get('label') or item.get('name') or 'Untitled',
+        "url": item.get('url'),
+        "id": item.get('id'),
+        "icon": item.get('icon'),
+        "menu": (item.get('id') is not none)
+    }] %}
+  {% endfor %}
+{% elif page_title %}
+  {% set ns.items = ns.items + [{
+      "label": page_title,
+      "url": none,
+      "id": nav_page_id if nav_page_id is defined else none,
+      "icon": page_icon if page_icon is defined else none,
+      "menu": (nav_page_id is defined and nav_page_id)
+  }] %}
+{% endif %}
 <header class="topbar unified-header">
   {% if not hide_hamburger %}
   <button class="hamburger-btn"
@@ -19,29 +46,172 @@
   </button>
   {% endif %}
 
-  <div class="topbar-left header-breadcrumb">
+  <script type="application/json" id="fd-breadcrumb-data">{{ {"workspace_id": nav_workspace_id|default(0), "crumbs": ns.items}|tojson }}</script>
+
+  <div class="topbar-left header-breadcrumb" x-data="fdBreadcrumb()" x-init="init()" @click.outside="closeAll()">
     {% if page_icon %}
     <span class="header-page-icon">{{ page_icon }}</span>
     {% endif %}
 
-    {% if breadcrumb_items %}
-      {% for item in breadcrumb_items %}
-        {% if item.url and not loop.last %}
-          <a href="{{ item.url }}" class="breadcrumb-link">{{ item.label }}</a>
-          <span class="breadcrumb-sep">/</span>
-        {% elif loop.last %}
-          <span class="breadcrumb-current">{{ item.label }}</span>
-        {% else %}
-          <span class="breadcrumb-link disabled">{{ item.label }}</span>
-          <span class="breadcrumb-sep">/</span>
-        {% endif %}
-      {% endfor %}
-    {% else %}
-      <span class="breadcrumb-current">{{ page_title|default('FlowDeck') }}</span>
-    {% endif %}
+    <template x-for="(crumb, di) in display" :key="di">
+      <span class="crumb-cell">
+        {# ── Collapsed "…" segment ── #}
+        <template x-if="crumb.ellipsis">
+          <span class="crumb-anchor">
+            <button type="button" class="breadcrumb-link crumb-ellipsis" @click.stop="toggleEllipsis()">&hellip;</button>
+            <div class="fd-nav-menu" x-show="ellipsisOpen" x-cloak x-transition.opacity>
+              <template x-for="h in crumb.hidden" :key="h.id">
+                <div class="fd-nav-item" @click.stop="go(h.url)">
+                  <span class="fd-nav-ico" x-text="h.icon || '📄'"></span>
+                  <span class="fd-nav-label" x-text="h.label"></span>
+                </div>
+              </template>
+            </div>
+          </span>
+        </template>
+
+        {# ── Plain link crumb (Home / non-menu with url) ── #}
+        <template x-if="!crumb.ellipsis && !crumb.menu && crumb.url">
+          <a class="breadcrumb-link" :href="crumb.url" x-text="crumb.label"></a>
+        </template>
+
+        {# ── Plain current crumb (no menu, no url) ── #}
+        <template x-if="!crumb.ellipsis && !crumb.menu && !crumb.url">
+          <span class="breadcrumb-current" x-text="crumb.label"></span>
+        </template>
+
+        {# ── Interactive crumb with navigation dropdown ── #}
+        <template x-if="!crumb.ellipsis && crumb.menu">
+          <span class="crumb-anchor">
+            <button type="button" class="breadcrumb-link"
+                    :class="{ 'breadcrumb-current': crumb.origIndex === crumbs.length - 1 }"
+                    @click.stop="openMenu(crumb.origIndex)"
+                    x-text="crumb.label"></button>
+            <div class="fd-nav-menu" x-show="openIdx === crumb.origIndex" x-cloak x-transition.opacity>
+              <div class="fd-nav-section">Private</div>
+              <template x-if="loading">
+                <div class="fd-nav-empty">Loading&hellip;</div>
+              </template>
+              <template x-if="!loading && activeItems.length === 0">
+                <div class="fd-nav-empty">No pages</div>
+              </template>
+              <template x-for="item in activeItems" :key="item.id">
+                <div class="fd-nav-item"
+                     @mouseenter="openSub(item)"
+                     @click.stop="go(item.url)">
+                  <span class="fd-nav-ico" x-text="item.icon || '📄'"></span>
+                  <span class="fd-nav-label" x-text="item.name"></span>
+                  <span class="fd-nav-arrow" x-show="item.has_children">&rsaquo;</span>
+                  <div class="fd-nav-menu fd-nav-submenu" x-show="subOpenId === item.id" x-cloak>
+                    <template x-for="s in subItems" :key="s.id">
+                      <div class="fd-nav-item" @click.stop="go(s.url)">
+                        <span class="fd-nav-ico" x-text="s.icon || '📄'"></span>
+                        <span class="fd-nav-label" x-text="s.name"></span>
+                        <span class="fd-nav-arrow" x-show="s.has_children">&rsaquo;</span>
+                      </div>
+                    </template>
+                  </div>
+                </div>
+              </template>
+            </div>
+          </span>
+        </template>
+
+        <span class="breadcrumb-sep" x-show="di < display.length - 1">/</span>
+      </span>
+    </template>
   </div>
 
   <div class="topbar-right header-actions">
     {{ right_actions|safe if right_actions else '' }}
   </div>
 </header>
+
+<script>
+document.addEventListener('alpine:init', function () {
+  if (window.Alpine && window.Alpine.__fdBreadcrumbRegistered) return;
+  if (window.Alpine) window.Alpine.__fdBreadcrumbRegistered = true;
+  Alpine.data('fdBreadcrumb', function () {
+    return {
+      crumbs: [],
+      wsId: 0,
+      openIdx: null,
+      ellipsisOpen: false,
+      loading: false,
+      cache: {},
+      activeItems: [],
+      subOpenId: null,
+      subItems: [],
+      init: function () {
+        var el = document.getElementById('fd-breadcrumb-data');
+        if (el) {
+          try {
+            var d = JSON.parse(el.textContent);
+            this.crumbs = (d.crumbs || []).map(function (c, i) { c.origIndex = i; return c; });
+            this.wsId = d.workspace_id || 0;
+          } catch (e) { this.crumbs = []; }
+        }
+      },
+      get display() {
+        var c = this.crumbs;
+        if (c.length <= 4) return c;
+        var head = [c[0], c[1]];
+        var hidden = c.slice(2, c.length - 2);
+        var tail = [c[c.length - 2], c[c.length - 1]];
+        return head.concat([{ ellipsis: true, hidden: hidden }], tail);
+      },
+      parentIdFor: function (origIndex) {
+        if (origIndex <= 0) return null;
+        var prev = this.crumbs[origIndex - 1];
+        return prev && prev.id ? prev.id : null;
+      },
+      fetchMenu: function (parentId) {
+        var key = parentId == null ? 'root' : String(parentId);
+        var self = this;
+        if (this.cache[key]) return Promise.resolve(this.cache[key]);
+        var url = '/api/nav/menu?';
+        if (this.wsId) url += 'workspace_id=' + this.wsId + '&';
+        if (parentId != null) url += 'parent_id=' + parentId;
+        return fetch(url, { credentials: 'same-origin' })
+          .then(function (r) { return r.json(); })
+          .then(function (d) { self.cache[key] = d.items || []; return self.cache[key]; })
+          .catch(function () { return []; });
+      },
+      openMenu: function (origIndex) {
+        var self = this;
+        if (this.openIdx === origIndex) { this.closeAll(); return; }
+        this.closeAll();
+        this.openIdx = origIndex;
+        this.loading = true;
+        this.fetchMenu(this.parentIdFor(origIndex)).then(function (items) {
+          if (self.openIdx === origIndex) { self.activeItems = items; }
+          self.loading = false;
+        });
+      },
+      openSub: function (item) {
+        var self = this;
+        if (!item.has_children) { this.subOpenId = null; this.subItems = []; return; }
+        if (this.subOpenId === item.id) return;
+        this.subOpenId = item.id;
+        this.subItems = [];
+        this.fetchMenu(item.id).then(function (items) {
+          if (self.subOpenId === item.id) { self.subItems = items; }
+        });
+      },
+      toggleEllipsis: function () {
+        var wasOpen = this.ellipsisOpen;
+        this.closeAll();
+        this.ellipsisOpen = !wasOpen;
+      },
+      closeAll: function () {
+        this.openIdx = null;
+        this.ellipsisOpen = false;
+        this.subOpenId = null;
+        this.subItems = [];
+        this.activeItems = [];
+      },
+      go: function (url) { if (url) window.location.href = url; }
+    };
+  });
+});
+</script>

app/templates/gitea_workspace.html

@@ -4,7 +4,7 @@
 {% block page_icon %}🔗{% endblock %}
 
 {% block topbar %}
-{% set breadcrumb_items = [{"label": "Home", "url": "/workspaces"}, {"label": owner ~ "/" ~ repo, "url": None}] %}
+{% set breadcrumb_items = [{"label": owner ~ "/" ~ repo, "url": None}] %}
 {% set page_icon = "🔗" %}
 {% set right_actions = '<button class="page-action-btn" @click="showNewFile=!showNewFile" title="New file">📄+</button><button class="page-action-btn" @click="triggerUpload()" title="Upload file">📤</button><input type="file" id="gitea-upload-input" style="display:none" @change="doUpload($event)" multiple><button class="page-action-btn" @click="refreshTree()" title="Refresh">🔄</button><a href="/accounts/settings" class="topbar-btn" title="Settings">⚙</a>' %}
 {% include '_header.html' %}

app/templates/workspaces.html

@@ -4,7 +4,7 @@
 {% block page_icon %}🏠{% endblock %}
 
 {% block topbar %}
-{% set breadcrumb_items = [{"label": "Home", "url": "/workspaces"}, {"label": "Workspaces", "url": None}] %}
+{% set breadcrumb_items = [{"label": "Workspaces", "url": None}] %}
 {% set page_icon = "🏠" %}
 {% set right_actions = '<a href="/auth/login?provider=local" class="topbar-btn" title="Login">🔑</a><a href="/accounts/settings" class="topbar-btn" title="Settings">⚙</a>' %}
 {% include '_header.html' %}