fix: corrige 6 bugs mineurs (BUG-035 a BUG-040)

backend/main.py

@@ -722,12 +722,56 @@ class SecurityHeadersMiddleware(BaseHTTPMiddleware):
         return response
 
 
+def _guard_insecure_auth() -> None:
+    """Warn or refuse to start when authentication is disabled (BUG-037).
+
+    With ``OBSIGATE_AUTH_ENABLED=false`` every request is served as an
+    anonymous admin. That is convenient for local use but dangerous when the
+    process is reachable from a network. Binding to a non-loopback host
+    without the explicit ``OBSIGATE_ALLOW_INSECURE=true`` opt-in is refused.
+    """
+    from backend.auth.middleware import (
+        bind_host_from_argv,
+        is_auth_enabled,
+        is_insecure_mode_allowed,
+        is_loopback_host,
+    )
+
+    if is_auth_enabled():
+        return
+
+    if is_insecure_mode_allowed():
+        logger.warning(
+            "Authentication is DISABLED and OBSIGATE_ALLOW_INSECURE=true: every request "
+            "is treated as an anonymous administrator. Do not expose this instance."
+        )
+        return
+
+    host = bind_host_from_argv()
+    if not is_loopback_host(host):
+        raise RuntimeError(
+            "Refusing to start: authentication is disabled (OBSIGATE_AUTH_ENABLED=false) "
+            f"while binding to a non-loopback address ('{host}'). This would expose an "
+            "unauthenticated instance with admin access. Enable authentication, or set "
+            "OBSIGATE_ALLOW_INSECURE=true if you really know what you are doing."
+        )
+
+    logger.warning(
+        "Authentication is DISABLED (OBSIGATE_AUTH_ENABLED=false): every request is "
+        "treated as an anonymous administrator. This is only safe on a trusted, "
+        "loopback-only deployment."
+    )
+
+
 @asynccontextmanager
 async def lifespan(app: FastAPI):
     """Application lifespan: build index on startup, cleanup on shutdown."""
     global _search_executor, _vault_watcher
     _search_executor = ThreadPoolExecutor(max_workers=2, thread_name_prefix="search")
-    
+
+    # BUG-037: refuse to expose an unauthenticated instance on a public bind.
+    _guard_insecure_auth()
+
     # Bootstrap admin account if needed
     bootstrap_admin()
 
@@ -748,6 +792,11 @@ async def lifespan(app: FastAPI):
         # Build the semantic (embedding) index in the same background thread pool.
         await loop.run_in_executor(_search_executor, init_semantic_index)
 
+        # BUG-040: extract the PDF text deferred during the scan now that the
+        # index and inverted index are queryable (keeps startup non-blocking).
+        from backend.indexer import enrich_pdf_texts
+        await enrich_pdf_texts()
+
         # Scan for plugins in all vaults
         logger.info("Scanning for plugins...")
         from backend.indexer import vault_config