feat: Add LanguageTool integration for comprehensive grammar checking

Integrated LanguageTool as an on-demand grammar checker, replacing the
previously disabled proselint checker.

Changes:
- Created scripts/languagetool-flycheck wrapper for flycheck integration
  - Converts LanguageTool JSON output to flycheck format
  - Includes suggestions in error messages
  - 30-second timeout for large files

- Updated modules/flycheck-config.el:
  - Defined languagetool checker for text/markdown/org/gfm modes
  - Updated cj/flycheck-prose-on-demand to use LanguageTool
  - Added installation instructions (sudo pacman -S languagetool)
  - Improved documentation clarity

- Usage: Press C-; ? in org/text/markdown files
  - Enables flycheck with LanguageTool
  - Shows errors in *Flycheck errors* buffer
  - On-demand only (no performance impact)

- Updated docs/NOTES.org:
  - Added best practice: Test Emacs launch after non-trivial changes
  - Example: emacs --eval "(kill-emacs)"
  - Catches startup errors before committing

- Disabled weather debug mode (wttrin-debug nil)

- Marked todo.org grammar checker task as DONE

LanguageTool catches real grammar issues (subject-verb agreement, tense,
punctuation, common mistakes) that proselint missed.

Installation: LanguageTool 6.6 (222MB) from Arch repos
Dependencies: Python 3 (for wrapper script)

0 files changed, 0 insertions, 0 deletions