feat: reminders due-date support + context filtering

reminders_add now accepts optional due: YYYY-MM-DD parameter.
Due date stored as first line of section body in REMINDERS.md.

context_loader.py calls load_due_reminders() instead of loading REMINDERS.md
wholesale — future-dated reminders are suppressed in the system prompt until
their date arrives. Undated reminders always surface (backward compatible).

reminders_list shows due status per entry: [OVERDUE by N days], [due TODAY],
or [due: YYYY-MM-DD] for future items. All reminders visible via the tool
regardless of date; only context surfacing is filtered.

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

cortex/context_loader.py

@@ -2,6 +2,7 @@ from datetime import datetime
 from pathlib import Path
 
 from persona import persona_path
+from tools.reminders import load_due_reminders
 
 _STATIC_DIR = Path(__file__).parent / "static"
 
@@ -80,12 +81,11 @@ def load_context(
         parts.append(f"--- HELP.md ---\n{help_path.read_text()}")
 
     # ── 4. Pending reminders (tier 2+) ────────────────────────────
-    #    Written by cron jobs; cleared by Inara after acting on them.
-    reminders_path = inara_dir / "REMINDERS.md"
-    if reminders_path.exists() and reminders_path.stat().st_size > 10:
-        content = reminders_path.read_text().strip()
-        if content:
-            parts.append(f"--- REMINDERS.md ---\n{content}")
+    #    Only due and undated reminders are surfaced — future-dated ones
+    #    are stored in REMINDERS.md but suppressed until their date arrives.
+    content = load_due_reminders()
+    if content:
+        parts.append(f"--- REMINDERS.md ---\n{content}")
 
     # ── 5. Tiered memory — long → mid → short ─────────────────────
     #    Short is last so it sits closest to the conversation turn.