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.

docs/rewrite/notes/windows-wine.md

@@ -0,0 +1,89 @@
+# Windows code under Wine (agent WINE)
+
+`just test-windows-wine` (= `scripts/windows-wine-test.sh [cargo test args]`)
+runs the `x86_64-pc-windows-gnu` test binaries under Wine 11.19 (staging) with
+the mingw-w64 toolchain. Dedicated `WINEPREFIX=target/wine-prefix`,
+`WINEDEBUG=-all`, no display (console tests only). `RUSTC_WRAPPER=` (kache
+breaks cc-rs), `RUSTFLAGS=--cfg wine` (lets tests mark Wine limitations as
+ignored; `cfg(wine)` is declared in the workspace lints and ghostty-termio),
+`WINEPATH` for the mingw runtime DLLs (libstdc++ from the bundled HarfBuzz).
+
+## Native dependencies
+
+Linking needs real libraries. The script builds them once into
+`target/wine-deps/prefix` (like Ghostty, from source): expat 2.6.4 (tarball is
+downloaded, or `EXPAT_TARBALL=`), FreeType (the sources vendored in
+`freetype-sys`) and fontconfig 2.14.2 (zig package cache copy, `FONTCONFIG_SRC=`,
+or a download) with cmake/meson cross builds. HarfBuzz/FreeType/oniguruma for
+the `-sys` crates come from their bundled features as before.
+
+## What ran (final run, exit 0)
+
+| crate | passed | ignored |
+|---|---|---|
+| ghostty-vt | 486 | 1 (pre-existing) |
+| ghostty-unicode | 20 | 0 |
+| ghostty-datastruct | 88 | 0 |
+| ghostty-input | 237 | 0 |
+| ghostty-os | 97 | 0 |
+| ghostty-config | 283 + 7 + 4 (integration) | 0 |
+| ghostty-terminal | 1275 | 0 |
+| ghostty-crash | 33 | 0 |
+| ghostty-termio | 107 lib + 2 golden + 10 `exec_windows` | 1 (Wine) |
+| ghostty-cli | 108 | 4 (Wine) |
+
+Before the fixes: cli 7, config 9, os 2, terminal 1, termio 15 failures and a
+link failure (below).
+
+`ghostty-termio/tests/exec_windows.rs` is the Windows counterpart of
+`exec_integration`: real `cmd.exe` children on a real ConPTY through
+`Termio` + `Thread` (`WaitForMultipleObjects` loop) + the pipe read thread
+against a real `Terminal`: `echo` output and exit status, `exit 7`, `Shell`
+command via `%WINDIR%\System32\cmd.exe /C`, interactive typing and exit code,
+120 KiB of input through the overlapped writer, resize messages
+(terminal + `ResizePseudoConsole`), `stop` terminating a running child,
+messages after exit, start failure shown in the terminal.
+
+## Bugs found and fixed
+
+* Link: `harfbuzz-sys` `bundled` is built without `HAVE_FREETYPE`, so
+  `hb_ft_font_create_referenced` was missing on Windows. `ghostty-font/build.rs`
+  now compiles `hb-ft.cc` against the bundled FreeType headers (Zig builds
+  HarfBuzz with FreeType). `cc` added as a build-dependency.
+* `std::fs::canonicalize` returns `\\?\C:\...` on Windows, Zig's `realpath`
+  returns `C:\...`; the verbatim form rejects `/` and is not usable as a
+  `cmd.exe` working directory. New `ghostty_os::path::realpath` strips it; used
+  by config path expansion, `+new-window`, `+validate-config`, kitty graphics
+  file loading, screen-file writes (faithfulness fix, not a Zig bug).
+* DEVIANT_FIXES 38: absolute Windows theme paths were rejected (`C:` looks like
+  a `light:`/`dark:` pair). DEVIANT_FIXES 39: `CreateProcessW` is called with a
+  literal `lpApplicationName`, so a bare `cmd.exe` argv[0] failed with
+  FileNotFound; PATH is searched first.
+* Tests with Unix assumptions fixed (platform-aware expectations, no product
+  change): shell-integration helpers (verbatim path, `;` PATH delimiter),
+  `xev::prefer(Iocp)` (Iocp is a candidate on Windows), i18n `init` (no-op on
+  Windows), kitty `/proc/` guard (POSIX only), config/theme/file-load
+  directory-open errors (Windows gives `AccessDenied` for a directory, matching
+  Zig 0.15 `OpenFile`; so `NotAFile` is `FileOpenFailed` there), path
+  separators, `light:`/`dark:` pairs need quoted backslashes (as in Zig),
+  `list_themes` file URIs (`file://C:%5C...`, as Zig's `toUri`).
+
+## Wine limitations (ignored with `wine:` reasons)
+
+* `ResizePseudoConsole` is a stub in Wine 11.19 (`fixme:console:
+  ResizePseudoConsole (100,40) stub, faking success`): the child never sees the
+  new size. `exec_windows::resize_is_applied_to_the_pseudo_console` is ignored;
+  the terminal-side resize and the API call are still tested.
+* `NtSetInformationFile(FileRenameInformationEx, REPLACE_IF_EXISTS|
+  POSIX_SEMANTICS)` is unsupported (`fixme:file:NtSetInformationFile
+  unsupported flags: 0x3`), so `std::fs::rename` over an existing file fails
+  with `ERROR_ACCESS_DENIED`. The four `ssh_cache` disk-cache tests (atomic
+  temp-file + rename) are ignored; real Windows supports it.
+* Wine's `cmd.exe` has no `mode con`, and its `findstr` ignores `/n`; tests use
+  a re-run of the test binary as console-size child and `%OS%` expansion.
+* Wine maps `/` to `Z:\`; tests on POSIX-looking paths account for it.
+
+## Not covered
+
+fontconfig/font discovery and the renderer/core/GTK crates are not run (no
+Windows apprt); ghostty-font links but its tests are not part of the run.