Enhance hooks with session-start script and documentation

- Add hooks/scripts/session-start.sh that:
  - Checks for unsummarized sessions
  - Checks for pending decisions
  - Outputs context to session
- Update hooks.json to use the script
- Add hooks/README.md documenting hook events and configuration

This provides automatic context loading at session start.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

hooks/README.md

@@ -0,0 +1,73 @@
+# Hooks
+
+Event handlers that run automatically during Claude Code sessions.
+
+## Active Hooks
+
+| Event | Script | Purpose |
+|-------|--------|---------|
+| `SessionStart` | `scripts/session-start.sh` | Load context, check for pending items |
+
+## Hook Events
+
+| Event | When It Fires |
+|-------|---------------|
+| `SessionStart` | When Claude Code session begins |
+| `SessionEnd` | When session ends |
+| `PreToolUse` | Before a tool is used |
+| `PostToolUse` | After a tool is used |
+| `UserPromptSubmit` | When user submits a prompt |
+| `PreCompact` | Before context compaction |
+| `Notification` | When notification is sent |
+
+## Configuration
+
+Hooks are defined in `hooks.json`:
+
+```json
+{
+  "hooks": {
+    "SessionStart": [
+      {
+        "hooks": [
+          {
+            "type": "command",
+            "command": "~/.claude/hooks/scripts/session-start.sh"
+          }
+        ]
+      }
+    ]
+  }
+}
+```
+
+## Adding Hooks
+
+1. Create script in `scripts/`
+2. Make executable: `chmod +x scripts/your-hook.sh`
+3. Add to `hooks.json`
+4. Restart Claude Code
+
+## Script Output
+
+- Stdout is injected into session as context
+- Use format: `HookName:Callback hook success: Success`
+- Additional context: `HookName hook additional context: <message>`
+
+## Matchers (for Tool Hooks)
+
+```json
+{
+  "matcher": "Write|Edit",
+  "hooks": [...]
+}
+```
+
+Matches tool names with regex pattern.
+
+## Tips
+
+- Keep hooks fast (<1s) to avoid delays
+- Use `set -euo pipefail` for safety
+- Output useful context, not noise
+- Test hooks manually before adding