v1.3.0: paywall-filter (Telegraaf/NHD premium) + staking-fix

- exclude_paywalled config (default true): verwijdert feedparser-entries met
  <premium>true</premium> vóór opslag (Telegraaf en NHD markeren dit; AD/
  Parool/Trouw/VK/NRC niet)
- v8-migratie: entry.paywalled BOOLEAN
- staking-fix (v1.2.3): losse 'staking/stakingen' uit filter; alleen ov-
  specifiek: ov-staking, bus/tram/metro/spoor/conducteurs-staking,
  'openbaar vervoer'
- config-proof: match_filter altijd enkelregelig YAML

buzzrss/migrations.py

@@ -94,3 +94,8 @@ async def upgrade_v6(conn: Connection) -> None:
 @upgrade_table.register(description="Remove per-subscription filter (single global config filter)")
 async def upgrade_v7(conn: Connection) -> None:
     await conn.execute("ALTER TABLE subscription DROP COLUMN IF EXISTS match_filter")
+
+
+@upgrade_table.register(description="Add paywalled flag to entries")
+async def upgrade_v8(conn: Connection) -> None:
+    await conn.execute("ALTER TABLE entry ADD COLUMN paywalled BOOLEAN NOT NULL DEFAULT false")