feat(MAT-174): Add cron job scheduler and executors

Cron package that syncs jobs from matrixhost portal API, schedules execution
with timezone-aware timing, and posts results to Matrix rooms. Includes
Brave Search, reminder, and browser scrape (placeholder) executors with
formatter. 31 pytest tests.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

cron/brave_search.py

@@ -0,0 +1,63 @@
+"""Brave Search executor for cron jobs."""
+
+import logging
+import os
+
+import httpx
+
+from .formatter import format_search_results
+
+logger = logging.getLogger(__name__)
+
+BRAVE_API_KEY = os.environ.get("BRAVE_API_KEY", "")
+
+
+async def execute_brave_search(job: dict, send_text, **_kwargs) -> dict:
+    """Run a Brave Search query, dedup against known keys, post new results to Matrix."""
+    if not BRAVE_API_KEY:
+        return {"status": "error", "error": "BRAVE_API_KEY not configured"}
+
+    config = job.get("config", {})
+    query = config.get("query", "")
+    max_results = config.get("maxResults", 10)
+    target_room = job["targetRoom"]
+    dedup_keys = set(job.get("dedupKeys", []))
+
+    if not query:
+        return {"status": "error", "error": "No search query configured"}
+
+    try:
+        async with httpx.AsyncClient(timeout=15.0) as client:
+            resp = await client.get(
+                "https://api.search.brave.com/res/v1/web/search",
+                headers={
+                    "Accept": "application/json",
+                    "X-Subscription-Token": BRAVE_API_KEY,
+                },
+                params={"q": query, "count": max_results, "text_decorations": False},
+            )
+            resp.raise_for_status()
+            data = resp.json()
+
+        results = data.get("web", {}).get("results", [])
+        if not results:
+            return {"status": "no_results"}
+
+        # Dedup by URL
+        new_results = [r for r in results if r.get("url") not in dedup_keys]
+
+        if not new_results:
+            return {"status": "no_results"}
+
+        msg = format_search_results(job["name"], new_results)
+        await send_text(target_room, msg)
+
+        new_keys = [r["url"] for r in new_results if r.get("url")]
+        return {
+            "status": "success",
+            "newDedupKeys": new_keys,
+        }
+
+    except Exception as exc:
+        logger.error("Brave search cron failed: %s", exc, exc_info=True)
+        return {"status": "error", "error": str(exc)}