docs: plan retained glyph text renderer

docs/platform-portability.md

@@ -33,7 +33,7 @@ or replaced before claiming portable exports.
 | AGE movie decode (`0x236` scene movies; `0x20f` modal LOGO/OP/ED; `0x24d` movie masks) | `FfmpegMovieDecoder` is the sole factory over the project-owned `native/age_movie_ffmpeg` ABI | Windows-x64 passes the complete 213-payload installed video/audio corpus gate plus audible LOGO/OP/CHAPTER playback and real TEST.AGF green-mask decode | Add target-specific native builds and export packaging |
 | Movie integration | Each surface owns a unique playback-instance id; `MovieRuntime` owns `IMovieDecoder` from an injected factory; video-only streams use monotonic pacing while audio-bearing streams use the Godot output clock. Opcode `0x24d` redirects decoded green bytes through the platform-neutral retained rasterizer and exact managed packed-alpha mask helper | Concurrent/restarted uses of one asset have independent frame/audio/completion/teardown state. Ordinary and mask movies share VFS/FFmpeg ownership; the mask result is a backend-neutral dynamic RGBA surface consumed by either Godot renderer. Managed code is no longer Windows-annotated, while only the win-x64 native bundle exists today | Add Linux/macOS native builds and smoke gates |
 | Movie audio | ABI v2 returns timestamped stereo float PCM; bounded managed buffering feeds a per-playback Godot `AudioStreamGenerator` and routes native movie flags to engine buses | All 29 installed audio-bearing streams decode with signal; synchronized LOGO/OP/CHAPTER playback is audibly accepted | Treat absent, distorted, or unsynchronized audio from an audio-bearing movie as a runtime bug |
-| ADV font discovery/raster fidelity | Opcode `0x1a5` reaches presentation; `godot/Main.cs` loads Windows `ＭＳ 明朝`/`ＭＳ ゴシック` from their known TTC files when available, otherwise uses the existing Japanese-font/default fallback. AGE actually uses a display information DC, weight-700 `LOGFONTA`, `GGO_GRAY4_BITMAP`, and its own integer glyph/outline compositor; the current `Label` backend substitutes FreeType embolden and a Godot outline | On the reference Windows install, regular advances and direct SC0000 placement/bounds agree, but the behaviorally different provisional bold path has 45% fewer bright pixels and much softer edge coverage. Other platforms normally lack the proprietary faces, so substitute metrics remain profile-dependent | Deferred until gameplay settles: implement the Phase-E decoded mask/metrics/compositor backlog in `docs/remake-architecture-and-roadmap.md`, with a shipped GDI reference backend on Windows and an explicitly defined portable rasterizer/substitution policy |
+| ADV font discovery/raster fidelity | Opcode `0x1a5` reaches presentation; `godot/Main.cs` loads Windows `ＭＳ 明朝`/`ＭＳ ゴシック` from their known TTC files when available, otherwise uses the existing Japanese-font/default fallback. AGE actually uses a display information DC, weight-700 `LOGFONTA`, `GGO_GRAY4_BITMAP`, and its own integer glyph/outline compositor; the current `Label` backend substitutes FreeType embolden and a Godot outline | On the reference Windows install, regular advances and direct SC0000 placement/bounds agree, but the behaviorally different provisional bold path has 45% fewer bright pixels and much softer edge coverage. Other platforms normally lack the proprietary faces, so substitute metrics remain profile-dependent | The Phase-E retained glyph-mask polish slice is now planned in `docs/remake-architecture-and-roadmap.md`: keep the GDI reference adapter outside the platform-neutral VM project, select it explicitly on Windows, and complete an explicitly non-identical portable rasterizer/substitution policy before removing the temporary Label fallback |
 | Filesystem semantics | Several filename and containment comparisons use `OrdinalIgnoreCase`; installed assets are conventionally uppercase | Needs validation on case-sensitive filesystems; may hide casing or containment mistakes | Add Linux/macOS tests with mixed-case synthetic roots and use filesystem-appropriate containment rules |
 | Save/profile/settings storage | `Sys4PersistencePaths` models AGE's independent `SAVEPATH` and `REGFILEPATH` resolutions. Godot replaces Himegari's related profile directory with `user://`, yielding `user://SAVE` for native S3SD/S4SD/S3RT files and thumbnails plus `user://SYS4REG.INI` for the BOM-less CP932 options file; the preserving writer changes only its nine `[sound]` keys | Save payloads and engine options are isolated together without changing either native format. Native/drop-in resolution remains available through `USEAPPDATAFOLDER` plus both SYS4INI paths. A single-root override is rejected when `SAVEPATH` is not beneath `REGFILEPATH`, preventing cross-profile guesses | Expose explicit profile/native selection through the future launcher and allow independent overrides for profiles whose two native paths are unrelated. Validate CP932 availability, replace/flush, case, permissions, and interrupted-write behavior on each export target |
 | Game-install and repository discovery | `GameRootSelection` accepts `--game-root`, then probes the executable directory and current working directory for `SYS4INI.BIN`; on Unix the frontend prefers inherited shell `PWD` because Godot may change the process directory during project startup. Godot injects the selected root into its catalog and loose-first ALF store. `Paths.cs` remains the development/test locator for generated opcode data, diagnostics, and CLI conveniences | Installed game data no longer depends on the workspace sibling layout, enabling an executable beside `AGE.EXE`, a terminal launch from the install, or a launcher-supplied absolute profile root. A packaged export still needs its generated runtime metadata bundled independently of repository discovery | Add export packaging for the opcode/profile artifacts, let the future profile launcher pass `--game-root`, and run executable-directory/CWD plus case/permission smoke gates on Linux and macOS |