feat: cron job system for Inara (remind + note types)

- cron_runner.py: job storage (CRONS.json), schedule parsing, execution
- tools/cron.py: cron_list/add/remove/toggle + reminders_clear tools
- scheduler.py: load user crons at startup, expose get_scheduler() for
  live add/remove without restarts
- context_loader.py: auto-include REMINDERS.md in system prompt (tier 2+)
  so cron reminders surface automatically without Inara having to poll
- inara/CRONS.json + REMINDERS.md: backing files (initially empty)

Schedule formats: hourly | daily | daily:HH:MM | weekly:DOW | weekly:DOW:HH:MM
Job types: remind (→ REMINDERS.md) | note (→ SCRATCH.md)

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

cortex/cron_runner.py

@@ -0,0 +1,161 @@
+"""
+Cron job storage and execution.
+
+Handles reading/writing CRONS.json and running jobs when they fire.
+Imported by scheduler.py (to load jobs at startup) and tools/cron.py
+(to add/remove jobs at runtime).
+
+Job schema:
+  {
+    "id":         "c_abc123",
+    "label":      "Human-readable name",
+    "schedule":   "daily:09:00",   # see parse_schedule() for all formats
+    "type":       "remind" | "note",
+    "payload":    "Text to write when the job fires",
+    "enabled":    true,
+    "created_at": "ISO 8601",
+    "last_run":   null | "ISO 8601"
+  }
+
+Job types:
+  remind  → appends to inara/REMINDERS.md  (auto-loaded into Inara's context)
+  note    → appends to inara/SCRATCH.md    (read on demand via scratch_read)
+"""
+
+import logging
+from datetime import datetime, timezone
+from pathlib import Path
+
+from config import settings
+
+logger = logging.getLogger(__name__)
+
+_DEFAULT_HOUR = 9
+_DEFAULT_MINUTE = 0
+
+_DOW = {
+    "mon": "mon", "tue": "tue", "wed": "wed", "thu": "thu",
+    "fri": "fri", "sat": "sat", "sun": "sun",
+    "monday": "mon", "tuesday": "tue", "wednesday": "wed",
+    "thursday": "thu", "friday": "fri", "saturday": "sat", "sunday": "sun",
+}
+
+
+# ---------------------------------------------------------------------------
+# Storage
+# ---------------------------------------------------------------------------
+
+def crons_path() -> Path:
+    return settings.inara_path() / "CRONS.json"
+
+
+def load_crons() -> list[dict]:
+    p = crons_path()
+    if not p.exists():
+        return []
+    try:
+        import json
+        return json.loads(p.read_text())
+    except Exception:
+        return []
+
+
+def save_crons(crons: list[dict]) -> None:
+    import json
+    crons_path().write_text(json.dumps(crons, indent=2) + "\n")
+
+
+# ---------------------------------------------------------------------------
+# Schedule parsing
+# ---------------------------------------------------------------------------
+
+def parse_schedule(schedule: str) -> dict:
+    """
+    Convert a human schedule string to APScheduler cron kwargs.
+
+    Formats:
+      "hourly"           → every hour at :00
+      "daily"            → every day at 09:00
+      "daily:HH:MM"      → every day at HH:MM
+      "weekly:DOW"       → every DOW at 09:00
+      "weekly:DOW:HH:MM" → every DOW at HH:MM
+    """
+    s = schedule.strip().lower()
+
+    if s == "hourly":
+        return {"minute": 0}
+
+    if s == "daily":
+        return {"hour": _DEFAULT_HOUR, "minute": _DEFAULT_MINUTE}
+
+    if s.startswith("daily:"):
+        h, m = _parse_hhmm(s[6:], schedule)
+        return {"hour": h, "minute": m}
+
+    if s.startswith("weekly:"):
+        rest = s[7:].split(":")
+        dow = _DOW.get(rest[0])
+        if not dow:
+            raise ValueError(
+                f"Unknown day of week {rest[0]!r}. "
+                f"Use: mon tue wed thu fri sat sun"
+            )
+        if len(rest) == 3:
+            h, m = _parse_hhmm(f"{rest[1]}:{rest[2]}", schedule)
+        else:
+            h, m = _DEFAULT_HOUR, _DEFAULT_MINUTE
+        return {"day_of_week": dow, "hour": h, "minute": m}
+
+    raise ValueError(
+        f"Unrecognised schedule {schedule!r}. "
+        f"Valid formats: hourly | daily | daily:HH:MM | weekly:DOW | weekly:DOW:HH:MM"
+    )
+
+
+def _parse_hhmm(s: str, original: str) -> tuple[int, int]:
+    parts = s.split(":")
+    if len(parts) != 2:
+        raise ValueError(f"Expected HH:MM in {original!r}, got {s!r}")
+    return int(parts[0]), int(parts[1])
+
+
+# ---------------------------------------------------------------------------
+# Execution
+# ---------------------------------------------------------------------------
+
+def _now_label() -> str:
+    return datetime.now(timezone.utc).strftime("%Y-%m-%d %H:%M UTC")
+
+
+async def run_job(job: dict) -> None:
+    """Execute a cron job. Called by APScheduler when the job fires."""
+    job_type = job.get("type")
+    payload = job.get("payload", "").strip()
+    label = job.get("label", job.get("id", "cron"))
+    section = f"\n## {label} — {_now_label()}\n\n{payload}\n"
+
+    inara_dir = settings.inara_path()
+
+    if job_type == "remind":
+        p = inara_dir / "REMINDERS.md"
+        existing = p.read_text() if p.exists() else ""
+        p.write_text(existing.rstrip() + "\n" + section)
+        logger.info("cron [remind] fired: %s", label)
+
+    elif job_type == "note":
+        p = inara_dir / "SCRATCH.md"
+        existing = p.read_text() if p.exists() else ""
+        p.write_text(existing.rstrip() + "\n" + section)
+        logger.info("cron [note] fired: %s", label)
+
+    else:
+        logger.warning("cron: unknown type %r (job %s)", job_type, job.get("id"))
+        return
+
+    # Record last_run
+    crons = load_crons()
+    for c in crons:
+        if c["id"] == job["id"]:
+            c["last_run"] = datetime.now(timezone.utc).isoformat()
+            break
+    save_crons(crons)