fix: resolve 3 critical UI bugs

1. Refresh button no longer doubles header
   - Added ?fragment=1 param to filter/refresh HTMX requests
   - Board route returns board_fragment.html (columns only) for fragment requests
   - Refresh button uses window.location.reload() for full page reload

2. No more raw JSON in header
   - base.html: user info rendered server-side via template variable
   - board.py: decodes session cookie, passes user to template
   - Dashboard/board templates show Login/Deconnexion based on auth state

3. New issue form works
   - Replaced HTMX post with JS fetch (handleNewIssue)
   - Adds CSRF token to form submission
   - Reloads page on successful creation
   - Cleaner error handling

app/routers/board.py

@@ -50,45 +50,32 @@ async def board(
     milestone: str = "",
     label: str = "",
     assignee: str = "",
+    fragment: bool = False,
 ):
     """Kanban board for a Gitea project."""
     try:
-        # Get issues
         issues = await gitea.get_issues(owner, repo, state="all")
-
-        # Get labels
-        labels = await gitea.get_labels(owner, repo)
-
-        # Get milestones
+        labels_list = await gitea.get_labels(owner, repo)
         milestones = await gitea.get_milestones(owner, repo)
 
-        # Filter by milestone
         if milestone:
             issues = [i for i in issues if i.get("milestone", {}).get("title") == milestone]
-
-        # Filter by label
         if label:
             issues = [i for i in issues if any(lbl["name"] == label for lbl in i.get("labels", []))]
-
-        # Filter by assignee
         if assignee:
             issues = [i for i in issues if i.get("assignee", {}).get("login") == assignee]
 
-        # Separate PRs from issues (ponytail: PRs are also in /issues endpoint)
         prs = [i for i in issues if "pull_request" in i]
         issues_only = [i for i in issues if "pull_request" not in i]
 
-        # Get board config
         board_info = _ensure_board(owner, repo)
         columns = board_info["columns"]
         cards = _get_cards(board_info["id"])
 
-        # Map issues to columns
         column_map: dict[str, list[dict]] = {col: [] for col in columns}
         card_by_issue = {c["gitea_issue_id"]: c for c in cards if c["gitea_issue_id"]}
 
         for issue in issues_only:
-            # Determine column from issue state/labels first, then from DB position
             col = _issue_column(issue, columns, board_info["id"])
             issue["_col"] = col
             issue["_card"] = card_by_issue.get(issue["number"])
@@ -97,37 +84,37 @@ async def board(
     except Exception as e:
         from httpx import HTTPStatusError
         if isinstance(e, HTTPStatusError) and e.response is not None and e.response.status_code == 404:
-            html = '<div style="padding:48px;text-align:center">'
-            html += '<h2 style="color:var(--text-dim)">Projet introuvable</h2>'
-            html += f'<p style="color:var(--text-dim)">{owner}/{repo} n\'existe pas sur Gitea.</p>'
-            html += '<a href="/" class="btn btn-primary" style="margin-top:16px">Retour aux projets</a>'
-            html += '</div>'
-            return HTMLResponse(html, status_code=404)
+            return HTMLResponse(
+                '<div style="padding:48px;text-align:center">'
+                f'<h2 style="color:#8b949e">Projet introuvable</h2>'
+                f'<p style="color:#8b949e">{owner}/{repo} n\'existe pas sur Gitea.</p>'
+                '<a href="/" class="btn btn-primary" style="margin-top:16px">Retour aux projets</a></div>',
+                status_code=404)
         logger.error("Board error: %s", e)
         return HTMLResponse(f"<p class='error'>Erreur: {e}</p>", status_code=500)
 
     from jinja2 import Environment, FileSystemLoader
     from datetime import datetime
     from app.config import settings
+    from app.auth.session import SessionManager
 
     env = Environment(loader=FileSystemLoader("app/templates"))
-    template = env.get_template("board.html")
-    return template.render(
-        request=request,
-        owner=owner,
-        repo=repo,
-        columns=columns,
-        column_map=column_map,
-        labels=labels,
-        milestones=milestones,
-        current_milestone=milestone,
-        current_label=label,
-        current_assignee=assignee,
-        prs=prs,
-        settings=settings,
-        now=datetime.now().isoformat()[:10],
+    now_str = datetime.now().isoformat()[:10]
+    user = SessionManager.decode_session(request.cookies.get("flowdeck_session", ""))
+
+    ctx = dict(
+        request=request, owner=owner, repo=repo, columns=columns,
+        column_map=column_map, labels=labels_list, milestones=milestones,
+        current_milestone=milestone, current_label=label, current_assignee=assignee,
+        prs=prs, settings=settings, now=now_str, user=user,
     )
 
+    if fragment:
+        template = env.get_template("board_fragment.html")
+    else:
+        template = env.get_template("board.html")
+    return template.render(**ctx)
+
 
 def _issue_column(issue: dict, columns: list[str], board_id: int) -> str:
     """Determine which column an issue belongs to."""