fix: side peek des bases repasse en vanilla JS + largeur 1100px standard (v7.49.0)

- Panneau peek: les bindings Alpine (x-data absent du conteneur) rendaient
  loovverture et le redimensionnement inoperants -> cblage direct sur le document.
- Helper unique window.fdWirePeekResize (app.js): pointer capture, 300px-90vw,
  clic=fermer, largeur persiste fd_peek_width partagee entre les 4 peeks.
- database-table-container margin:0 (tableau colle a gauche, marge Library).
- .lib-container remonte dans app.css (trash etait pleine largeur), .db-index 1100px.
- ObsiGate verifie sans code: creation .xlsx OK (openpyxl, #186).

app/routers/admin.py

@@ -104,6 +104,10 @@ def update_user(user_id: int, request: Request, _admin=Depends(admin_required),
 def delete_user(user_id: int, _admin=Depends(admin_required)):
     """Delete a user and cascade their data."""
     from app.db import get_conn
+    from app.services.collection_lifecycle import (
+        delete_collections,
+        workspace_collection_ids,
+    )
     with get_conn() as conn:
         user = conn.execute("SELECT id FROM users WHERE id=?", (user_id,)).fetchone()
         if not user:
@@ -121,6 +125,9 @@ def delete_user(user_id: int, _admin=Depends(admin_required)):
         # Delete workspaces owned by this user
         ws_rows = conn.execute("SELECT id FROM workspaces WHERE owner_id=?", (user_id,)).fetchall()
         for ws in ws_rows:
+            # Les bases du workspace tombent avec lui (sinon : collections
+            # orphelines listées par /db et My Tasks).
+            delete_collections(conn, workspace_collection_ids(conn, ws["id"]))
             conn.execute("DELETE FROM pages WHERE workspace_id=?", (ws["id"],))
             conn.execute("DELETE FROM workspace_members WHERE workspace_id=?", (ws["id"],))
         conn.execute("DELETE FROM workspaces WHERE owner_id=?", (user_id,))