fix(settings): accept numeric values in update payload

Svelte bind:value on <input type="number"> coerces to a JS number, so the
frontend sends {telegram_cache_ttl_hours: 0} after v0.2.4. Pydantic v2
won't auto-coerce int -> str, which produced a 422 on every save that
touched a numeric setting.

- Widen numeric fields to int | str | None in SettingsUpdate.
- Normalize to str before persisting (DB column is text).

packages/server/src/notify_bridge_server/api/app_settings.py

@@ -56,10 +56,14 @@ async def get_setting(session: AsyncSession, key: str) -> str:
 
 
 class SettingsUpdate(BaseModel):
+    # Numeric fields declared as int|str so clients can send either form.
+    # Svelte's bind:value on <input type="number"> coerces to a JS number,
+    # so the frontend sends ints for these; older/manual clients may send
+    # strings. We normalize to str before persisting.
     external_url: str | None = None
     telegram_webhook_secret: str | None = None
-    telegram_cache_ttl_hours: str | None = None
+    telegram_cache_ttl_hours: int | str | None = None
-    telegram_asset_cache_max_entries: str | None = None
+    telegram_asset_cache_max_entries: int | str | None = None
     supported_locales: str | None = None
     timezone: str | None = None
 
@@ -95,11 +99,12 @@ async def update_settings(
         value = getattr(body, key, None)
         if value is None:
             continue
+        value_str = str(value)
         row = await session.get(AppSetting, key)
         if row:
-            row.value = value
+            row.value = value_str
         else:
-            row = AppSetting(key=key, value=value)
+            row = AppSetting(key=key, value=value_str)
         session.add(row)
     await session.commit()