refactor(heartbeat): config-driven checks, channel delivery, remove hardcoded values

Heartbeat system overhaul:
- Fix email/calendar checks to parse JSON output correctly
- Add per-check cooldowns and quiet hours config
- Send findings to Discord channel instead of just logging
- Auto-reindex KB when stale files detected
- Claude CLI called only if HEARTBEAT.md has extra instructions
- All settings configurable via config.json heartbeat section

Move hardcoded values to config.json:
- allowed_tools list (claude_session.py)
- Ollama URL/model (memory_search.py now reads ollama.url from config)

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

config.json

@@ -26,8 +26,46 @@
   },
   "heartbeat": {
     "enabled": true,
-    "interval_minutes": 30
+    "interval_minutes": 30,
+    "channel": "echo-core",
+    "model": "haiku",
+    "quiet_hours": [23, 8],
+    "checks": {
+      "email": true,
+      "calendar": true,
+      "kb_index": true,
+      "git": true
+    },
+    "cooldowns": {
+      "email": 1800,
+      "calendar": 0,
+      "kb_index": 14400,
+      "git": 14400
+    }
   },
+  "allowed_tools": [
+    "Read", "Edit", "Write", "Glob", "Grep",
+    "WebFetch", "WebSearch",
+    "Bash(python3 *)", "Bash(.venv/bin/python3 *)",
+    "Bash(pip *)", "Bash(pytest *)",
+    "Bash(git add *)", "Bash(git commit *)",
+    "Bash(git push)", "Bash(git push *)",
+    "Bash(git pull)", "Bash(git pull *)",
+    "Bash(git status)", "Bash(git status *)",
+    "Bash(git diff)", "Bash(git diff *)",
+    "Bash(git log)", "Bash(git log *)",
+    "Bash(git checkout *)",
+    "Bash(git branch)", "Bash(git branch *)",
+    "Bash(git stash)", "Bash(git stash *)",
+    "Bash(npm *)", "Bash(node *)", "Bash(npx *)",
+    "Bash(systemctl --user *)",
+    "Bash(trash *)", "Bash(mkdir *)", "Bash(cp *)",
+    "Bash(mv *)", "Bash(ls *)", "Bash(cat *)", "Bash(chmod *)",
+    "Bash(docker *)", "Bash(docker-compose *)", "Bash(docker compose *)",
+    "Bash(ssh *@10.0.20.*)", "Bash(ssh root@10.0.20.*)",
+    "Bash(ssh echo@10.0.20.*)",
+    "Bash(scp *10.0.20.*)", "Bash(rsync *10.0.20.*)"
+  ],
   "ollama": {
     "url": "http://localhost:11434"
   },