refactor(core): centralize constants and resolve log path discrepancy

[JacksonFergusonDev]

Summary

This refactor decouples logic from configuration by converting constants.py into a pure data module and centralizing all magic strings (file paths, app labels, ignore patterns).

It also resolves a critical "split-brain" logging issue where the CLI and Daemon were reading/writing to different log files.

Changes

• Core Refactor (constants.py):

  • Removed _get_state_dir function; path resolution is now handled via top-level constants.
  • Centralized APP_LABEL, DEFAULT_IGNORES, and GIT_LOCK_FILES.
  • Added explicit Path type hints to satisfy strict static analysis.

• Bug Fix (cli.py):

  • Pointed tail_log to the centralized LOG_FILE constant (XDG State) instead of the hardcoded legacy path (~/.git_pulsar_log).
  • Replaced hardcoded .gitignore defaults with the centralized list.

• Daemon & Service:

  • Updated daemon.py and service.py to import APP_LABEL and paths from constants rather than defining them locally.
  • Added explicit type casting in system.py to prevent Returning Any errors in strict mode.

Verification

1. Logging: Run git-pulsar log. It should now correctly tail the active daemon log located in ~/.local/state/git-pulsar/daemon.log (or equivalent XDG path).
2. Constants: Verify constants.py contains no def statements.