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/scripts/session-start.sh

@@ -0,0 +1,47 @@
+#!/bin/bash
+# Session start hook - provides context to Claude
+# Output is injected into the session as a system reminder
+
+set -euo pipefail
+
+CLAUDE_DIR="${HOME}/.claude"
+STATE_DIR="${CLAUDE_DIR}/state"
+PA_DIR="${STATE_DIR}/personal-assistant"
+
+# Check for unsummarized sessions
+UNSUMMARIZED=0
+if [[ -f "${PA_DIR}/history/index.json" ]]; then
+    UNSUMMARIZED=$(python3 -c "
+import json
+with open('${PA_DIR}/history/index.json') as f:
+    data = json.load(f)
+    unsummarized = [s for s in data.get('sessions', []) if not s.get('summarized', False)]
+    print(len(unsummarized))
+" 2>/dev/null || echo "0")
+fi
+
+# Check for pending memory items
+PENDING_DECISIONS=0
+if [[ -f "${PA_DIR}/memory/decisions.json" ]]; then
+    PENDING_DECISIONS=$(python3 -c "
+import json
+with open('${PA_DIR}/memory/decisions.json') as f:
+    data = json.load(f)
+    pending = [d for d in data.get('items', []) if d.get('status') == 'pending']
+    print(len(pending))
+" 2>/dev/null || echo "0")
+fi
+
+# Output context as system reminder format
+echo "SessionStart:Callback hook success: Success"
+
+# Add additional context if there's something noteworthy
+if [[ "${UNSUMMARIZED}" -gt 0 || "${PENDING_DECISIONS}" -gt 0 ]]; then
+    echo "SessionStart hook additional context: "
+    if [[ "${UNSUMMARIZED}" -gt 0 ]]; then
+        echo "- ${UNSUMMARIZED} unsummarized session(s) available for review"
+    fi
+    if [[ "${PENDING_DECISIONS}" -gt 0 ]]; then
+        echo "- ${PENDING_DECISIONS} pending decision(s) to review"
+    fi
+fi