fix: inspector font/formatting, FreeType-only backend on Apple

Resolves the parity items of docs/rewrite/notes/review-rv17-codex.md
(final-Z20.md):
- FreeType-only font backend is also available on Apple targets
  (discovery-free, embedded emoji fonts); ghostty_surface_quicklook_font
  returns null for every backend except plain CoreText like Zig.
- The +list-fonts test keys off the font crate's selected backend
  (HAS_DISCOVERY), correct under feature unification and on Apple.
- Inspector font: 32 px rasterized with FreeType (dear-imgui freetype)
  like Ghostty; a new `visual-parity.sh inspector` scenario shows 0.031%
  differing pixels (hover highlight) vs the original on Linux. Windows,
  Apple and wasm keep stb_truetype at 32 px (registered as a deliberate
  deviation).
- Inspector DCS/APC descriptions follow Zig 0.15.2's formatting
  (checked by running Zig), incl. the terminal.Parser.Action prefix.
- The ImGui demo window appears only in dev-profile builds, mirroring
  Zig's .Debug-only gate.

Test Plan:
- cargo test --workspace --no-fail-fast (3582 passed)
- just check-macos (both, also with --features font-backend-freetype)
- scripts/visual-parity.sh inspector

docs/rewrite/DEVIANT_FIXES.md

@@ -98,6 +98,7 @@ Only entries with an observable behavioural difference are listed.
 | `+version` / build info | Real build metadata | Placeholder `build_info` values in places; `gtk-opengl-debug` follows `cfg!(debug_assertions)` (the `release` profile has them on, `production` off) | `notes/ghostty-cli.md`, `notes/ghostty-config.md` | 6286e02 |
 | OSC 52 base64 acceptance | Surface.zig:2149,2163 rules | Was different in both directions (Codex core audit); fixed to match Zig | `notes/review-core-codex.md` | 2f58f02 |
 | Benchmark / synthetic tooling extensions | `ghostty-bench` has no `--time` option and only the simplified terminal handler; `ghostty-synthetic` has the actions `ascii`, `osc`, `utf8` | `ghostty-bench --time` prints the measured step time to stderr; `ghostty-bench --handler=full` runs the full `stream_readonly` handler instead of the print-only one; `ghostty-synthetic +sgr` generates SGR-heavy output. Dev/benchmark tooling only; otherwise upstream behaviour is unchanged | `crates/ghostty-bench/src/main.rs`, `src/benches.rs`, `src/bin/ghostty-synthetic.rs`; `notes/review-rv16-codex.md` | 0c4f0ee |
+| Inspector font rasterizer (Windows, Apple, wasm) | Dear ImGui is built with `IMGUI_ENABLE_FREETYPE` (`pkg/dcimgui`), so the 32 px inspector font is rasterized by FreeType | Linux and other Unix targets: FreeType (`dear-imgui-rs` feature `freetype`, system FreeType through pkg-config), 32 px. Windows, Apple and wasm32 keep Dear ImGui's stb_truetype loader at 32 px, because `dear-imgui-sys` can only locate FreeType through pkg-config/vcpkg and those targets cannot be built or run here. Glyph anti-aliasing differs slightly there. | `crates/ghostty-inspector/Cargo.toml`, `src/inspector.rs` (`embedded_font_source`) | Z20 (uncommitted) |
 
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