test(windows): run the Windows code under Wine; theme preview parity

Windows was previously only compile-checked. With Wine 11 (staging)
and mingw available, scripts/windows-wine-test.sh (`just
test-windows-wine`) builds expat/FreeType/fontconfig for mingw under
target/wine-deps and runs the test suites of ghostty-vt, unicode,
datastruct, input, os, config, terminal, crash, termio and cli under
Wine (~2,700 tests). New termio/tests/exec_windows.rs drives real
cmd.exe children over ConPTY through Termio (output, exit codes,
typing, 120 KiB writes, stop, start failure). Fixes found: Windows
paths from fs::canonicalize leaked the \\?\ prefix (new
ghostty_os::path::realpath strips it like Zig); ghostty-font compiles
hb-ft for bundled HarfBuzz on Windows; ~25 tests had Unix assumptions.
Wine limitations are ignored with reasons (ResizePseudoConsole stub,
no POSIX rename over existing files) - docs/rewrite/notes/windows-wine.md.

+list-themes preview parity (former KNOWN_DIFFERENCES rows 5-9): the
search box ports vaxis TextInput (word navigation and editing bindings,
grapheme-wise editing), ASCII-only case folding, light initial colors
until terminal reports arrive (no COLORFGBG), and load errors end the
preview with exit 1; PTY tests compare with /usr/bin/ghostty.

Test Plan:
- just test-windows-wine
- cargo test -p ghostty-cli --test list_themes_pty
- cargo test --workspace --no-fail-fast (3601 passed)

docs/rewrite/notes/final-P3.md

@@ -0,0 +1,22 @@
+# P3: KNOWN_DIFFERENCES rows 5-10
+
+* 5/6 `ghostty-cli/src/list_themes/preview.rs` `TextInput` is now a port of
+  `vaxis.widgets.TextInput`: byte cursor, grapheme-wise Backspace/Delete/Left/Right
+  (`unicode-segmentation`), ASCII-space words for Alt+B/F (and Alt+Left/Right),
+  Ctrl+W / Alt+Backspace, Alt+D, Ctrl+A/E/K/U/B/F/D. Modifiers must match exactly
+  (vaxis `Key.matches`), e.g. Ctrl+Left is not Left.
+* 7 `rank` lowers only ASCII and compares bytes (zf `std.ascii.toLower`).
+* 8 `initial_scheme`/`COLORFGBG` removed: light until a color-scheme report arrives.
+* 9 `Preview::new`, `update_filtered`, `update`, `handle_terminal_event` return
+  `Result`; `load_file` errors propagate and end the preview (exit code 1, as Zig).
+* 10 `ghostty-termio/src/exec.rs` `getpgid`: no 5 s cap, waits like Zig. Deviation
+  (DEVIANT_FIXES.md #13): Zig spins forever if the child died before `setsid`
+  and is an unreaped zombie (pgid stays ours); Rust stops when `waitid(WNOWAIT)`
+  reports the child exited.
+
+Tests: unit tests in `preview.rs` and `exec.rs`; PTY tests in
+`tests/list_themes_pty.rs` (Rust binary vs `/usr/bin/ghostty`, oracle part skipped
+when absent; uses `setsid --ctty`, needs util-linux).
+
+Observed, not fixed (outside rows 5-10): a ZWJ emoji cluster (woman+ZWJ+rocket) in
+the search box is drawn by Rust without the second emoji; Zig draws it.