Add Cursor hook setup

[Siddhant-K-code]

Summary

• Add Cursor as a supported hook provider for agent-strace hook and agent-strace setup --cli cursor.
• Generate .cursor/hooks.json or $CURSOR_CONFIG_DIR/hooks.json with Cursor prompt, shell, file-edit, response, and session lifecycle command hooks.
• Normalize Cursor hook payloads into the existing trace events, including shell tool calls and file-write events.
• Document Cursor setup and the current coverage limits; MCP proxy tracing remains the reliable path for MCP server tool calls.
• Bump package version to 0.79.0.

Closes #174.

Verification

• python3 -m pytest tests/test_cursor_hooks.py tests/test_codex_hooks.py tests/test_gemini_hooks.py -q -> 21 passed
• python3 -m compileall -q src/agent_trace && git diff --check
• python3 -m agent_trace.cli --version -> agent-strace 0.79.0
• python3 -m pytest tests/ -q -> 1602 passed
• wc -l README.md -> 221