feat(app): add plugin system with auth plugin and static assets

Add new application structure:
- app/main.py - application entry point
- app/plugins/ - plugin system with auth plugin:
  - api/ - REST API endpoints and schemas
  - authorization/ - auth policies, providers, hooks
  - domain/ - business logic (service, models, jwt, password)
  - injection/ - route injection and guards
  - ops/ - operational utilities
  - runtime/ - runtime configuration
  - security/ - middleware, CSRF, dependencies
  - storage/ - user repositories and models
- app/static/ - static assets (scalar.js for API docs)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

backend/app/plugins/auth/injection/validation.py

@@ -0,0 +1,38 @@
+"""Validation helpers for config-driven auth route policies."""
+
+from __future__ import annotations
+
+from fastapi import FastAPI
+from fastapi.routing import APIRoute
+
+from app.plugins.auth.injection.registry_loader import RoutePolicyRegistry
+
+_IGNORED_METHODS = frozenset({"HEAD", "OPTIONS"})
+
+
+def _iter_route_keys(app: FastAPI) -> set[tuple[str, str]]:
+    keys: set[tuple[str, str]] = set()
+    for route in app.routes:
+        if not isinstance(route, APIRoute):
+            continue
+        for method in route.methods:
+            if method in _IGNORED_METHODS:
+                continue
+            keys.add((method, route.path))
+    return keys
+
+
+def validate_route_policy_registry(app: FastAPI, registry: RoutePolicyRegistry) -> None:
+    route_keys = _iter_route_keys(app)
+    missing = sorted(route_keys - registry.keys)
+    extra = sorted(registry.keys - route_keys)
+    problems: list[str] = []
+    if missing:
+        problems.append("Missing route policy entries:\n" + "\n".join(f"  - {method} {path}" for method, path in missing))
+    if extra:
+        problems.append("Unknown route policy entries:\n" + "\n".join(f"  - {method} {path}" for method, path in extra))
+    if problems:
+        raise RuntimeError("\n\n".join(problems))
+
+
+__all__ = ["validate_route_policy_registry"]