refactor(face-restore): drop GFPGAN, ship PhotoMaker-V2 as the sole restore (non-commercial)

Visual review of the GFPGAN-on-cleaned output (9-face grid, 1448x1086) showed it
only polished the already-drifted face without restoring identity — useless for the
"restore who is in the photo" intent. Dropping it.

The shipped restore path is now PhotoMaker-V2, which delivers true identity-from-
embedding face regeneration via a CLIP+ArcFace dual encoder. The ArcFace branch
pulls InsightFace antelopev2/buffalo_l model packs at runtime, which InsightFace
releases under a research-only license, so the whole extra is **NON-COMMERCIAL**.
raiw.cc and any monetized deployment must NOT install the `photomaker` extra.
This is called out at every entry point: CLI flag help, module docstring,
pyproject extra block, CLAUDE.md extras bullet, README install snippet.

Changes:
- Deleted `src/remove_ai_watermarks/face_restore.py` and its tests.
- Deleted the `restore` extra (gfpgan/facexlib/basicsr + scipy<1.18 / numba<0.60
  pins) and the basicsr setuptools<69 build pin from pyproject.toml.
- Restored `src/remove_ai_watermarks/photomaker_restore.py` (V2 this time:
  `TencentARC/PhotoMaker-V2`, `photomaker-v2.bin`, no `pm_version='v1'` override).
- Restored the `photomaker` extra in pyproject with all the upstream-compat
  pins (einops, peft, onnxruntime, insightface) and the `allow-direct-references`
  hatch metadata block.
- `InvisibleEngine` swapped `_restore_faces` -> `_restore_faces_photomaker`;
  `--restore-faces-method` removed (only one method, no choice).
- CLI flag help, CLAUDE.md, README, docs/synthid.md, and
  docs/controlnet-removal-pipeline-research.md all updated.
- docs/synthid-robust-identity-research.md status notice rewritten to list both
  abandoned commercial-safe attempts (V1 + GFPGAN-on-cleaned) and the
  non-commercial trade-off we accepted.

ruff + strict pyright(src/) clean; 578 tests pass (the 9 GFPGAN tests are gone,
the 11 PhotoMaker tests stay green).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/remove_ai_watermarks/cli.py

@@ -238,16 +238,18 @@ def _warn_if_esrgan_unavailable(upscaler: str) -> None:
 def _restore_faces_options(f: Any) -> Any:
     """Attach the face-restoration flag to an invisible-pipeline command.
 
-    The post-pass runs GFPGAN on the DIFFUSION-CLEANED image (not the original), so
-    SynthID is not re-introduced (the input pixels GFPGAN derives from are already
-    SynthID-free). See ``face_restore.py``.
+    The post-pass uses PhotoMaker-V2 to regenerate each face from a CLIP+ArcFace
+    embedding. **NON-COMMERCIAL** -- PhotoMaker-V2 pulls InsightFace antelopev2/
+    buffalo_l model packs at runtime, which are research-only. A paid service
+    (raiw.cc, any monetized SaaS) MUST NOT use this flag.
     """
     return click.option(
         "--restore-faces/--no-restore-faces",
         default=False,
-        help="EXPERIMENTAL, opt-in. Polish face detail with a GFPGAN post-pass on the "
-        "cleaned image when faces are present (needs the 'restore' extra); off by default, "
-        "auto-skips when no face is detected or the extra is absent.",
+        help="EXPERIMENTAL, opt-in, **NON-COMMERCIAL** -- needs the 'photomaker' extra "
+        "which pulls non-commercial InsightFace model packs. Restores face identity via "
+        "PhotoMaker-V2 (CLIP+ArcFace embedding -> fresh face); off by default, auto-skips "
+        "when no face is detected or the extra is absent.",
     )(f)