fix: resolve TypeScript error detection issues

[dmmulroy]

Summary

This PR fixes three critical issues that prevented tsc.nvim from detecting TypeScript errors that were visible when running pnpm run typecheck or tsc directly, while maintaining 100%
backward compatibility with existing configurations.

Root Causes Fixed

1. Auto-detection override: The default config always called find_nearest_tsconfig() for the project flag, overriding user configurations. Now auto-detection only occurs when no
   explicit project is configured.

2. ANSI color parsing: TypeScript outputs colored text by default, but the regex parser expected plain text. Fixed by automatically adding --color false flag (unless user explicitly
   sets color = true).

3. Working directory mismatch: The plugin ran from the current buffer directory instead of project root. Fixed by setting cwd option in jobstart() to the project root directory.

Key Changes

• lua/tsc/init.lua:

  • Removed hardcoded project function from default config
  • Added proper working directory handling in monorepo loop
  • Enhanced error validation and handling

• lua/tsc/utils.lua:

  • Added conditional auto-detection logic in parse_flags()
  • Added automatic --color false flag (respects user override)
  • Updated find_nearest_tsconfig() to return absolute paths in array format
  • Added get_project_root() helper function

• lua/tsc/utils-test.lua:

  • Comprehensive test suite covering all utility functions
  • Tests for each bug fix to prevent regression
  • Edge cases and error condition testing

• Documentation:

  • Updated README.md with accurate configuration examples
  • Added CLAUDE.md with bug fix details and architecture notes
  • Clarified automatic color flag behavior

Monorepo Integration

This PR has been updated to work seamlessly with the new monorepo features:

• ✅ Full compatibility with run_as_monorepo = true
• ✅ Works with Trouble integration (use_trouble_qflist = true)
• ✅ Supports diagnostics mode (use_diagnostics = true)
• ✅ Compatible with all new commands (TSCStop, TSCOpen, TSCClose)

Backward Compatibility

✅ 100% backward compatible - all existing configurations continue to work:

• String flags: flags = "--noEmit --watch" ✅
• Function-based project: project = function() return "path" end ✅
• Object flags: flags = { noEmit = true, project = "/path" } ✅
• Auto-detection: flags = { noEmit = true } (auto-finds tsconfig) ✅
• Color overrides: flags = { color = true } ✅

Migration Path

Users can migrate gradually:

-- Old format (still works)
flags = "--noEmit --watch"

-- New format (recommended)
flags = { noEmit = true, watch = true }

-- With explicit overrides
flags = { noEmit = true, color = true, project = "/custom/path" }

Test Plan

- Test with different TypeScript project structures (single project, monorepo)
- Test with different tsc versions and configurations
- Verify compatibility with existing user configurations
- Test manual :TSC command and watch mode functionality
- Test new monorepo features (run_as_monorepo = true)
- Test Trouble integration (use_trouble_qflist = true)
- Test diagnostics mode (use_diagnostics = true)
- Comprehensive unit tests for all utility functions
- Test edge cases and error conditions
- Verify all new commands work (TSCStop, TSCOpen, TSCClose)

Before/After

Before: Plugin reported "No errors found" even when tsc showed errors
After: Plugin detects same errors as pnpm run typecheck or tsc directly

Files Changed

- lua/tsc/init.lua - Main plugin integration with monorepo support
- lua/tsc/utils.lua - Core utility functions with bug fixes
- lua/tsc/utils-test.lua - Comprehensive test suite (new file)
- README.md - Updated documentation with accurate configuration
- CLAUDE.md - Development notes and architecture documentation (new file)

The plugin now properly detects TypeScript errors while maintaining full backward compatibility and supporting all new monorepo, Trouble, and diagnostics features.