feat: Enhanced data capture with new hooks and session tracking

Phase 1 of v2 upgrade:
- Add PreToolUse hook for true "running" state before tool execution
- Add UserPromptSubmit hook to track user prompts and idle state
- Add Stop hook for idle detection when Claude finishes responding
- Add PreCompact hook to track context compaction events
- Enrich capture-event.sh with permission_mode, transcript_path, cwd
- Add CostTracker for session cost estimation
- Add SessionInfo type for tracking session state
- Show idle indicator (💤/⚡) and permission mode in header
- Show cost estimate when significant
- Show compaction count warning
- Show last user prompt preview

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

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

scripts/capture-event.sh

@@ -7,9 +7,14 @@ if [ -p "$EVENT_FIFO" ]; then
   echo "$INPUT" | jq -c '{
     event: .hook_event_name,
     tool: .tool_name,
+    toolUseId: .tool_use_id,
     input: .tool_input,
     response: .tool_response,
     session: .session_id,
+    permissionMode: .permission_mode,
+    transcriptPath: .transcript_path,
+    cwd: .cwd,
+    prompt: .prompt,
     ts: (now | floor)
   }' >> "$EVENT_FIFO" 2>/dev/null || true
 fi