feat: points 11a + 11b — Indicateur AI Actif & Page d'accueil voute

Point 11a — Indicateur AI Actif:
- Badge sync flashe en blanc pendant traitement AI (animation CSS)
- Événements ai-processing-start/end dans ai.js
- Section statut IA dans panneau sync (configurée/non configurée/en cours)
- Endpoint GET /api/ai/status vérifiant les clés API configurées

Point 11b — Page d'accueil de voute:
- Endpoint GET /api/vault/{vault}/files?dir=... (trié par mtime)
- Module vaulthome.js: affichage style résultats de recherche
- Breadcrumb navigable, mise à jour auto sur clic dossier dans tree
- Déclenché auto quand un vault spécifique est sélectionné

backend/main.py

@@ -2162,6 +2162,21 @@ async def api_file_restore(
         raise HTTPException(status_code=500, detail=f"Error restoring file: {str(e)}")
 
 
+@app.get("/api/ai/status")
+async def api_ai_status(current_user=Depends(require_auth)):
+    """Return the AI configuration status.
+
+    Checks whether any AI provider API key is configured.
+    Does NOT expose the key itself, only a boolean 'configured' flag.
+    """
+    providers = ["DEEPSEEK_API_KEY", "OPENROUTER_API_KEY", "GEMINI_API_KEY"]
+    configured = any(
+        os.environ.get(env_var, "").strip()
+        for env_var in providers
+    )
+    return {"configured": configured, "providers_checked": providers}
+
+
 @app.get("/api/file/{vault_name}/backlinks")
 async def api_file_backlinks(
     vault_name: str,
@@ -3068,6 +3083,82 @@ async def api_update_vault_settings(vault_name: str, body: dict = Body(...), cur
     return updated
 
 
+@app.get("/api/vault/{vault_name}/files")
+async def api_vault_recent_files(
+    vault_name: str,
+    dir: str = Query("", description="Directory path within the vault (empty = root)"),
+    limit: int = Query(100, description="Maximum number of files to return"),
+    current_user=Depends(require_auth),
+):
+    """List files in a vault directory sorted by modification time (newest first).
+
+    Returns file metadata suitable for a vault home page display.
+    Unlike /api/browse, this endpoint sorts by mtime and returns
+    additional metadata (size, modified time, extension).
+
+    Args:
+        vault_name: Name of the vault.
+        dir: Relative directory path within the vault (empty for root).
+        limit: Maximum files to return (default 100).
+
+    Returns:
+        JSON with vault, directory, and list of file entries.
+    """
+    if not check_vault_access(vault_name, current_user):
+        raise HTTPException(status_code=403, detail=f"Accès refusé à la vault '{vault_name}'")
+
+    vault_data = get_vault_data(vault_name)
+    if not vault_data:
+        raise HTTPException(status_code=404, detail=f"Vault '{vault_name}' not found")
+
+    vault_root = Path(vault_data["path"])
+    dir_path = _resolve_safe_path(vault_root, dir) if dir else vault_root
+
+    if not dir_path.exists() or not dir_path.is_dir():
+        raise HTTPException(status_code=404, detail=f"Directory not found: {dir}")
+
+    files = []
+    ignored = {'.obsidian', '.trash', '.git', '.obsigate-backup', '__pycache__', 'node_modules'}
+
+    try:
+        for entry in dir_path.iterdir():
+            if entry.name.startswith('.') and entry.name not in ('.', '..'):
+                continue
+            if entry.name in ignored:
+                continue
+            if not entry.is_file():
+                continue
+
+            stat = entry.stat()
+            rel_path = str(entry.relative_to(vault_root)).replace("\\", "/")
+            ext = entry.suffix.lower() if entry.suffix else ""
+
+            files.append({
+                "name": entry.name,
+                "path": rel_path,
+                "vault": vault_name,
+                "size": stat.st_size,
+                "modified": stat.st_mtime,
+                "modified_iso": datetime.fromtimestamp(stat.st_mtime, tz=timezone.utc).isoformat(),
+                "extension": ext.lstrip(".") if ext else "",
+            })
+    except PermissionError:
+        raise HTTPException(status_code=403, detail="Permission denied reading directory")
+
+    # Sort by modification time, newest first
+    files.sort(key=lambda f: f["modified"], reverse=True)
+
+    # Apply limit
+    files = files[:limit]
+
+    return {
+        "vault": vault_name,
+        "directory": dir,
+        "count": len(files),
+        "files": files,
+    }
+
+
 @app.get("/api/vaults/settings/all")
 async def api_get_all_vault_settings(current_user=Depends(require_auth)):
     """Get UI display settings for all vaults.