fix: dashboard.py duplicate /pages/{id} route was intercepting embed requests

Root cause: dashboard.router registered BEFORE board.router in main.py,
so dashboard's /pages/{page_id} handler got all requests and ignored
the embed parameter. board.py's embed-aware route was never reached.

Fix: add embed support to dashboard.py's view_page_root too:
- Detect ?embed=1 query param
- Select page_editor_embed.html when embed=True
- Pass embed_mode to template context

app/routers/dashboard.py

@@ -280,7 +280,9 @@ async def library_page(request: Request, owner: str = Query(default=""), repo: s
 
 @router.get("/pages/{page_id}", response_class=HTMLResponse)
 async def view_page_root(request: Request, page_id: int):
-    """Render a Markdown page at root level with workspace context — or file viewer."""
+    """Render a Markdown page at root level with workspace context — or file viewer.
+    ?embed=1 — minimal mode for side peek (editor only, no header)."""
+    embed = request.query_params.get("embed") == "1"
     from jinja2 import Environment, FileSystemLoader
     from app.routers.board import _sidebar_data as board_sidebar
     env = Environment(loader=FileSystemLoader("app/templates"))
@@ -342,8 +344,9 @@ async def view_page_root(request: Request, page_id: int):
            "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")
+           "nav_page_id": page_id,
+           "embed_mode": embed}
+    template = env.get_template("page_editor_embed.html" if embed else "page_editor.html")
     response = template.render(**ctx)
     return HTMLResponse(content=response, headers={"Cache-Control": "no-store, max-age=0"})