feat: metadata enrichment for alerts and subscription plugins

Alert backends now populate structured `extra` field with engagement
metrics (views, stars, votes, etc.) instead of embedding them in titles.
Subscription plugins show richer announcements: Twitch viewer counts,
YouTube views/likes/dates, RSS published dates.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

tests/test_alert.py

@@ -19,6 +19,7 @@ _spec.loader.exec_module(_mod)
 
 from plugins.alert import (  # noqa: E402
     _MAX_SEEN,
+    _compact_num,
     _delete,
     _errors,
     _extract_videos,
@@ -27,6 +28,7 @@ from plugins.alert import (  # noqa: E402
     _pollers,
     _restore,
     _save,
+    _save_result,
     _search_searx,
     _search_twitch,
     _search_youtube,
@@ -179,6 +181,10 @@ class _FakeBot:
     async def reply(self, message, text: str) -> None:
         self.replied.append(text)
 
+    async def long_reply(self, message, lines, *, label: str = "") -> None:
+        for line in lines:
+            self.replied.append(line)
+
     def _is_admin(self, message) -> bool:
         return self._admin
 
@@ -223,9 +229,9 @@ def _fake_tw(keyword):
     """Fake Twitch backend returning two results (keyword in title)."""
     return [
         {"id": "stream:tw1", "title": "TW test Stream 1",
-         "url": "https://twitch.tv/user1", "extra": ""},
+         "url": "https://twitch.tv/user1", "extra": "500 viewers"},
         {"id": "vod:tw2", "title": "TW test VOD 1",
-         "url": "https://twitch.tv/videos/tw2", "extra": ""},
+         "url": "https://twitch.tv/videos/tw2", "extra": "1k views"},
     ]
 
 
@@ -322,6 +328,36 @@ class TestTruncate:
         assert not result.endswith(" ...")
 
 
+# ---------------------------------------------------------------------------
+# TestCompactNum
+# ---------------------------------------------------------------------------
+
+class TestCompactNum:
+    def test_zero(self):
+        assert _compact_num(0) == "0"
+
+    def test_small(self):
+        assert _compact_num(999) == "999"
+
+    def test_one_k(self):
+        assert _compact_num(1000) == "1k"
+
+    def test_one_point_five_k(self):
+        assert _compact_num(1500) == "1.5k"
+
+    def test_one_m(self):
+        assert _compact_num(1000000) == "1M"
+
+    def test_two_point_five_m(self):
+        assert _compact_num(2500000) == "2.5M"
+
+    def test_exact_boundary(self):
+        assert _compact_num(10000) == "10k"
+
+    def test_large_millions(self):
+        assert _compact_num(12300000) == "12.3M"
+
+
 # ---------------------------------------------------------------------------
 # TestExtractVideos
 # ---------------------------------------------------------------------------
@@ -873,6 +909,13 @@ class TestPollOnce:
             assert "[poll/yt/" in actions[0]
             assert "[poll/tw/" in actions[2]
             assert "[poll/sx/" in actions[4]
+            # Twitch fakes have extra metadata; verify it appears in titles
+            tw_titles = [s for t, s in bot.sent if t == "#test" and "TW test" in s]
+            assert any("| 500 viewers" in t for t in tw_titles)
+            assert any("| 1k views" in t for t in tw_titles)
+            # YouTube fakes have no extra; verify no pipe suffix
+            yt_titles = [s for t, s in bot.sent if t == "#test" and "YT test" in s]
+            assert all("|" not in t for t in yt_titles)
 
         asyncio.run(inner())
 
@@ -1239,3 +1282,103 @@ class TestSearchSearx:
         with patch("urllib.request.urlopen", side_effect=ConnectionError("fail")):
             results = _search_searx("test")
         assert results == []
+
+
+# ---------------------------------------------------------------------------
+# TestExtraInHistory
+# ---------------------------------------------------------------------------
+
+class TestExtraInHistory:
+    def test_history_shows_extra(self):
+        """History output includes | extra suffix when extra is non-empty."""
+        _clear()
+        bot = _FakeBot()
+        data = {
+            "keyword": "test", "name": "hist", "channel": "#test",
+            "interval": 300, "seen": {}, "last_poll": "", "last_error": "",
+        }
+        _save(bot, "#test:hist", data)
+        # Insert a result with extra metadata
+        _save_result("#test", "hist", "hn", {
+            "id": "h1", "title": "Cool HN Post", "url": "https://hn.example.com/1",
+            "date": "2026-01-15", "extra": "42pt 10c",
+        })
+
+        async def inner():
+            await cmd_alert(bot, _msg("!alert history hist"))
+            assert len(bot.replied) >= 1
+            found = any("| 42pt 10c" in line for line in bot.replied)
+            assert found, f"Expected extra in history, got: {bot.replied}"
+
+        asyncio.run(inner())
+
+    def test_history_no_extra(self):
+        """History output has no pipe when extra is empty."""
+        _clear()
+        bot = _FakeBot()
+        data = {
+            "keyword": "test", "name": "hist2", "channel": "#test",
+            "interval": 300, "seen": {}, "last_poll": "", "last_error": "",
+        }
+        _save(bot, "#test:hist2", data)
+        _save_result("#test", "hist2", "yt", {
+            "id": "y1", "title": "Plain Video", "url": "https://yt.example.com/1",
+            "date": "", "extra": "",
+        })
+
+        async def inner():
+            await cmd_alert(bot, _msg("!alert history hist2"))
+            assert len(bot.replied) >= 1
+            assert all("|" not in line for line in bot.replied)
+
+        asyncio.run(inner())
+
+
+# ---------------------------------------------------------------------------
+# TestExtraInInfo
+# ---------------------------------------------------------------------------
+
+class TestExtraInInfo:
+    def test_info_shows_extra(self):
+        """Info output includes | extra suffix when extra is non-empty."""
+        _clear()
+        bot = _FakeBot()
+        data = {
+            "keyword": "test", "name": "inf", "channel": "#test",
+            "interval": 300, "seen": {}, "last_poll": "", "last_error": "",
+        }
+        _save(bot, "#test:inf", data)
+        short_id = _save_result("#test", "inf", "gh", {
+            "id": "g1", "title": "cool/repo: A cool project",
+            "url": "https://github.com/cool/repo",
+            "date": "2026-01-10", "extra": "42* 5fk",
+        })
+
+        async def inner():
+            await cmd_alert(bot, _msg(f"!alert info {short_id}"))
+            assert len(bot.replied) >= 1
+            assert "| 42* 5fk" in bot.replied[0]
+
+        asyncio.run(inner())
+
+    def test_info_no_extra(self):
+        """Info output has no pipe when extra is empty."""
+        _clear()
+        bot = _FakeBot()
+        data = {
+            "keyword": "test", "name": "inf2", "channel": "#test",
+            "interval": 300, "seen": {}, "last_poll": "", "last_error": "",
+        }
+        _save(bot, "#test:inf2", data)
+        short_id = _save_result("#test", "inf2", "yt", {
+            "id": "y2", "title": "Some Video",
+            "url": "https://youtube.com/watch?v=y2",
+            "date": "", "extra": "",
+        })
+
+        async def inner():
+            await cmd_alert(bot, _msg(f"!alert info {short_id}"))
+            assert len(bot.replied) >= 1
+            assert "|" not in bot.replied[0]
+
+        asyncio.run(inner())