feat(news): F0 — schema, config y métodos DB del monitor RSS (inerte)

news_seen table (CREATE TABLE IF NOT EXISTS, sin migración) + índices.
Config NEWS_* (NEWS_ENABLED=false por defecto) + propiedad news_chat_id
(fallback al 1er TELEGRAM_ALLOWED_USERS). Métodos ResearchDB: source_seeded,
record_news_item, mark_news_notified, get_recent_news. Todo inerte: nada
lo invoca aún. feedparser ya estaba en requirements (6.0.12 >= 6.0).

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

src/db/database.py

@@ -115,6 +115,22 @@ CREATE TABLE IF NOT EXISTS watched_topics (
     created_at REAL NOT NULL,
     UNIQUE(topic, chat_id)
 );
+
+CREATE TABLE IF NOT EXISTS news_seen (
+    id INTEGER PRIMARY KEY,
+    source TEXT NOT NULL,
+    guid TEXT NOT NULL,
+    title TEXT,
+    link TEXT,
+    published_at TEXT,
+    matched_keywords TEXT,
+    seen_at TEXT DEFAULT (datetime('now')),
+    notified INTEGER DEFAULT 0,
+    UNIQUE(source, guid)
+);
+
+CREATE INDEX IF NOT EXISTS idx_news_seen_source ON news_seen(source);
+CREATE INDEX IF NOT EXISTS idx_news_seen_seen ON news_seen(seen_at);
 """
 
 
@@ -496,6 +512,56 @@ class ResearchDB:
         )
         await self.db.commit()
 
+    # --- News monitor ---
+
+    async def source_seeded(self, source: str) -> bool:
+        """True si ya hemos visto algún item de esta fuente (cold-start por fuente:
+        el primer poll siembra sin notificar)."""
+        cursor = await self.db.execute(
+            "SELECT 1 FROM news_seen WHERE source = ? LIMIT 1", (source,)
+        )
+        return await cursor.fetchone() is not None
+
+    async def record_news_item(self, source: str, guid: str, title: str,
+                               link: str, published_at: str, matched: str,
+                               notified: int) -> bool:
+        """INSERT OR IGNORE de un item. Devuelve True solo si es una inserción
+        real (item nuevo); False si ya existía (UNIQUE(source, guid))."""
+        cursor = await self.db.execute(
+            """INSERT OR IGNORE INTO news_seen
+               (source, guid, title, link, published_at, matched_keywords, notified)
+               VALUES (?, ?, ?, ?, ?, ?, ?)""",
+            (source, guid, title, link, published_at, matched, notified)
+        )
+        await self.db.commit()
+        return cursor.rowcount > 0
+
+    async def mark_news_notified(self, ids: list[int]):
+        if not ids:
+            return
+        placeholders = ",".join("?" for _ in ids)
+        await self.db.execute(
+            f"UPDATE news_seen SET notified = 1 WHERE id IN ({placeholders})",
+            tuple(ids)
+        )
+        await self.db.commit()
+
+    async def get_recent_news(self, hours: int = 24) -> list[dict]:
+        """Items matcheados cuya seen_at (o published_at parseable) cae en la
+        ventana. Orden por published_at desc, con seen_at como desempate."""
+        window = f"-{int(hours)} hours"
+        cursor = await self.db.execute(
+            """SELECT * FROM news_seen
+               WHERE seen_at >= datetime('now', ?)
+                  OR (published_at IS NOT NULL AND published_at != ''
+                      AND datetime(published_at) >= datetime('now', ?))
+               ORDER BY published_at DESC, seen_at DESC
+               LIMIT 50""",
+            (window, window)
+        )
+        rows = await cursor.fetchall()
+        return [dict(r) for r in rows]
+
     # --- Maintenance ---
 
     async def purge_old_sessions(self, max_age_days: int = 30) -> dict: