feat: add occurrence check to poster before strategy dispatch

Parse the occurrence field from sub_row and skip execution when today
is not the nth weekday specified (e.g. first_sunday). Check runs after
sub_row fetch but before dupe guard. Two new tests confirm skip and
pass paths using patched date.today in app.services.poster.

app/services/poster.py

@@ -6,11 +6,13 @@ from __future__ import annotations
 
 import asyncio
 import logging
+from datetime import date
 from pathlib import Path
 
 from app.core.config import get_settings
 from app.db.store import Store
 from app.services.platforms import get_client
+from app.services.platforms.reddit_comment import is_nth_weekday, parse_occurrence
 
 logger = logging.getLogger(__name__)
 
@@ -36,6 +38,18 @@ def _run_post(db_path: str, campaign_id: int, target: str,
         all_subs = store.list_campaign_subs(campaign_id)
         sub_row = next((s for s in all_subs if s["sub"] == target), {})
 
+        # Occurrence check — skip if not the right week of the month
+        occurrence_str = (sub_row or {}).get("occurrence")
+        parsed = parse_occurrence(occurrence_str)
+        if parsed is not None:
+            weekday, n = parsed
+            if not is_nth_weekday(date.today(), weekday, n):
+                logger.info(
+                    "Skipping %s / %s — not occurrence %s today",
+                    campaign_id, target, occurrence_str,
+                )
+                return {"skipped": True, "reason": f"occurrence {occurrence_str} not today"}
+
         # Dupe guard (opt-out allowed per strategy)
         if strategy.supports_dupe_guard() and store.already_posted_this_week(campaign_id, target):
             return {"skipped": True, "reason": f"already posted to {target!r} this week"}

tests/services/test_poster.py

@@ -113,3 +113,52 @@ def test_run_post_unknown_type_skips(tmp_path):
 
     assert result["skipped"] is True
     assert "Unknown campaign type" in result["reason"]
+
+
+def test_occurrence_skip(tmp_path):
+    """When occurrence is 'first_sunday' and today is NOT the first Sunday, post is skipped."""
+    db = str(tmp_path / "test.db")
+    # 2026-04-19 is a Sunday but the 3rd Sunday of April 2026
+    mock_store = _make_store(
+        campaign_type="reddit_comment",
+        subs=[{"sub": "selfhosted", "active": 1, "occurrence": "first_sunday"}],
+    )
+    mock_strategy = MagicMock()
+    mock_strategy.supports_dupe_guard.return_value = False
+
+    with patch("app.services.poster.Store", return_value=mock_store):
+        with patch("app.services.poster.get_client", return_value=mock_strategy):
+            with patch("app.services.poster.date") as mock_date:
+                from datetime import date as real_date
+                mock_date.today.return_value = real_date(2026, 4, 19)
+                result = _run_post(db, campaign_id=1, target="selfhosted", triggered_by="scheduler")
+
+    assert result["skipped"] is True
+    assert "occurrence" in result["reason"]
+    mock_strategy.execute.assert_not_called()
+
+
+def test_occurrence_passes(tmp_path):
+    """When occurrence is 'first_sunday' and today IS the first Sunday, post proceeds."""
+    db = str(tmp_path / "test.db")
+    # 2026-05-03 is the first Sunday of May 2026
+    mock_store = _make_store(
+        campaign_type="reddit_comment",
+        subs=[{"sub": "selfhosted", "active": 1, "occurrence": "first_sunday"}],
+    )
+    mock_result = MagicMock()
+    mock_result.url = "https://reddit.com/r/selfhosted/comments/abc/"
+
+    mock_strategy = MagicMock()
+    mock_strategy.supports_dupe_guard.return_value = False
+    mock_strategy.execute.return_value = mock_result
+
+    with patch("app.services.poster.Store", return_value=mock_store):
+        with patch("app.services.poster.get_client", return_value=mock_strategy):
+            with patch("app.services.poster.date") as mock_date:
+                from datetime import date as real_date
+                mock_date.today.return_value = real_date(2026, 5, 3)
+                result = _run_post(db, campaign_id=1, target="selfhosted", triggered_by="scheduler")
+
+    assert result.get("skipped") is not True
+    mock_strategy.execute.assert_called_once()