feat: Web-Such-Budget pro Nutzer/Tag

Neue Tabelle web_search_usage + Store-Zaehler (web_search_count /
add_web_search_usage, kaskadiert in delete_user). Pro-Nutzer-Limit
web_search_daily_limit (Pref > global; 0 = unbegrenzt) in quota.py
(web_search_within_budget). ws.py: Gate vor _resolve (Budget aufgebraucht ->
Web-Suche fuer den Turn aus) + Zaehlung nach dem Turn (trace.web_searches,
gezaehlt im Orchestrator je on_citations). Admin: Feld + UI-Eingabe.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

app/store.py

@@ -120,6 +120,14 @@ class Store(ABC):
     def add_usage(self, user_id: str, units: int = 0, day: str | None = None) -> int:
         """Zaehlt eine Anfrage (+units) und liefert die neue Tages-Anfragezahl."""
 
+    @abstractmethod
+    def web_search_count(self, user_id: str, day: str | None = None) -> int:
+        """Anzahl Web-Suchen des Nutzers am Tag (Default: heute, UTC)."""
+
+    @abstractmethod
+    def add_web_search_usage(self, user_id: str, n: int = 1, day: str | None = None) -> int:
+        """Zaehlt n Web-Suchen dazu und liefert die neue Tages-Zahl."""
+
     @abstractmethod
     def delete_user(self, user_id: str) -> bool:
         """Loescht einen Nutzer und alle seine Daten (Sessions, Nachrichten, Erinnerungen,
@@ -229,6 +237,12 @@ class SQLiteStore(Store):
                     units INTEGER NOT NULL DEFAULT 0,
                     PRIMARY KEY (user_id, day)
                 );
+                CREATE TABLE IF NOT EXISTS web_search_usage (
+                    user_id TEXT NOT NULL,
+                    day TEXT NOT NULL,
+                    count INTEGER NOT NULL DEFAULT 0,
+                    PRIMARY KEY (user_id, day)
+                );
                 CREATE TABLE IF NOT EXISTS emergency_events (
                     id INTEGER PRIMARY KEY AUTOINCREMENT,
                     user_id TEXT NOT NULL,
@@ -480,6 +494,29 @@ class SQLiteStore(Store):
             ).fetchone()
         return int(row["requests"])
 
+    def web_search_count(self, user_id: str, day: str | None = None) -> int:
+        day = day or self._today()
+        with self._connect() as conn:
+            row = conn.execute(
+                "SELECT count FROM web_search_usage WHERE user_id = ? AND day = ?",
+                (user_id, day),
+            ).fetchone()
+        return int(row["count"]) if row else 0
+
+    def add_web_search_usage(self, user_id: str, n: int = 1, day: str | None = None) -> int:
+        day = day or self._today()
+        with self._connect() as conn:
+            conn.execute(
+                "INSERT INTO web_search_usage (user_id, day, count) VALUES (?, ?, ?)"
+                " ON CONFLICT(user_id, day) DO UPDATE SET count = count + excluded.count",
+                (user_id, day, int(n)),
+            )
+            row = conn.execute(
+                "SELECT count FROM web_search_usage WHERE user_id = ? AND day = ?",
+                (user_id, day),
+            ).fetchone()
+        return int(row["count"])
+
     def delete_user(self, user_id: str) -> bool:
         if user_id == ANONYMOUS_USER_ID:
             raise ValueError("Der anonyme Nutzer kann nicht geloescht werden.")
@@ -494,6 +531,7 @@ class SQLiteStore(Store):
             conn.execute("DELETE FROM sessions WHERE user_id = ?", (user_id,))
             conn.execute("DELETE FROM memories WHERE user_id = ?", (user_id,))
             conn.execute("DELETE FROM usage WHERE user_id = ?", (user_id,))
+            conn.execute("DELETE FROM web_search_usage WHERE user_id = ?", (user_id,))
             conn.execute("DELETE FROM users WHERE id = ?", (user_id,))
         return True