Add Cursor Agent session indexing (Closes #9)

[driftfox]

Summary

This PR adds indexing and search for Cursor Agent transcripts (Cursor IDE and agent CLI) stored under ~/.cursor/projects/**/agent-transcripts/<uuid>/<uuid>.jsonl.

Closes #9.

Changes

• scripts/recall.py

  • New parse_cursor_session() parser for Cursor JSONL format
  • Glob and index canonical uuid/uuid.jsonl files only
  • Project path from Shell working_directory in tool_use blocks, with slug decode fallback
  • Session timestamp from file mtime
  • New --source cursor filter
  • --project matches path prefix or substring (helps names like quick-gtasks)
  • Skip numeric-only project slugs during decode

• scripts/read_session.py

  • Detect Cursor transcripts by path (/.cursor/projects/ and /agent-transcripts/)
  • Pretty-print user and assistant text blocks

• tests/test_cursor_parser.py

  • Synthetic JSONL fixtures for parser, slug decode, and format detection
  • Optional integration test against real ~/.cursor/projects/ when present

• Docs

  • SKILL.md, README.md, and CHANGELOG.md updated for v0.5.0
  • Resume instructions: agent --resume <session-uuid>

Upgrade note

Existing users should run once after upgrading:

python3 ~/.claude/skills/recall/scripts/recall.py --reindex "test"

Test plan

• python -m unittest discover tests -v (35 tests, 1 skipped when no pi sessions on host)
• recall "sorting" --project quick-gtasks --source cursor returns Cursor sessions on a host with transcripts
• read_session.py <cursor-transcript.jsonl> prints user and assistant turns

Notes

• Cursor JSONL has no per-message timestamps; mtime is used for recency sorting
• Slug decode cannot recover hyphens inside folder names (e.g. quick-gtasks); working_directory from Shell tool calls is preferred when available
• Transcript layout verified on Cursor 3.4.x (Windows); macOS and Linux paths should be confirmed by maintainers if needed