feat: initial implementation of mousefree

Keyboard-driven mouse navigation overlay for Wayland using
wlr-layer-shell and wlr-virtual-pointer. Two-key grid selection,
click/double-click/right-click/drag, three-tier cursor nudge
(hjkl/HJKL/Ctrl+hjkl), and scroll passthrough.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

CHANGELOG.md

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+# Changelog
+
+## [1.0.0] - 2026-04-03
+
+### Added
+
+- Keyboard-driven grid overlay for Wayland compositors
+- Two-key cell selection (column + row) with 10x16 grid
+- Cursor nudging with `hjkl` / `HJKL` / `Ctrl+hjkl` / `Alt+hjkl` (1 px)
+- Left-click, double-click, triple-click (`Shift+Enter`), and right-click
+- Click-and-drag with animated pointer interpolation
+- Scroll pass-through via arrow keys
+- Undo/backspace to step back one selection phase
+- Context-sensitive status bar with key hints
+- System font discovery via fontconfig (`fc-match`)
+
+### Requirements
+
+- Wayland compositor with `wlr-layer-shell` and `wlr-virtual-pointer`
+- fontconfig
+- US QWERTY keyboard layout