Delete every knob the fixed profiles cannot honor

The CLI still advertised --model, --steps, --guidance-scale, --device and a
deprecated --auto. Each pinned a value the two surviving profiles fix -- the
model stack, the per-stage distilled schedule, CFG 1.0, CUDA -- so the only
outcome any of them had was an error raised several frames below the caller,
under a message naming an internal profile. A flag whose sole result is a
refusal is worse than no flag: it advertises a capability that does not exist,
and it lets a wrapper thread a value that will silently do nothing. They are
gone from the parser, from InvisibleEngine, and from WatermarkRemover, so the
failure is now a TypeError or a Click "No such option" at the point the caller
can act on.

The install hint was wrong in the same way. is_available() checked torch and
diffusers, then told the user to install [diffusion] -- which contains neither
DiffSynth nor the Z-Image face stage both profiles run. Following the advice
produced a second, different failure. The module list and the extra name now
live once in watermark_profiles (REMOVAL_MODULES, INVISIBLE_EXTRA) and are read
by both the CLI gate and the remover's precondition, which cannot drift apart
because they are the same tuple.

The adaptive-polish default moved out of the argument parser. It was resolved by
reading Click's parameter source, which put per-profile data in the CLI layer,
left the engine declaring the opposite default (False vs True) so a library
caller and a CLI caller on one profile got different output, and lost the polish
entirely for anything that supplies the flag non-interactively. The flag is now
tri-state (default=None) and resolve_adaptive_polish owns the per-profile
answer. The seed follows the same rule: the CLI stopped pre-resolving it.

Dead code removed with it: six scan_*_video wrappers and the _scan_video helper
none of them had a caller for, PNG_METADATA_KEYS, feather_region_composite and
the remover region path that was only reachable from a no-caller convenience
wrapper, remove_watermark_batch on both layers, try_empty_device_cache, the
_generate/_run_qwen_zimage pass-through pair, self.model_id, and the _internal
PEP 562 shim that no caller ever went through. get_device now answers cuda or
cpu only: mps and xpu travelled one frame to the same CUDA-only refusal while
costing a device probe each, and that refusal now names the resolved device, so
device=None on a CUDA-less host says 'cpu' rather than 'None'. The XPU wheel
index went with them.

Docs: README, cli, installation, python-api, supported-signals,
known-limitations and module-internals all still described the removed profiles,
the CPU/MPS/XPU ladder, a `default`->`sdxl` alias, and the wrong extra.
known-limitations still listed the retired SDXL strength ladder as current.
scripts/smoke_matrix.py and real_examples_e2e.py drove --device mps.

Next release is 0.25.0, not a patch: this removes public parameters and
narrows a published extra on top of the released 0.24.0.

pre-commit: 1) maintain.sh - exit 0 (1091 tests, Pyright 0 errors, no
vulnerabilities); 2) /simplify - 4 agents, 11 findings applied, 2 skipped
(dropping the `device` parameter entirely, which raiw-app pins; folding
diffsynth into the `diffusion` extra, which video-only callers do not need);
3) docs sync - grepped every removed identifier across README, docs/, scripts/,
.claude/; updated 9 docs; 4) CLAUDE.md - added the no-error-only-knobs rule to
.claude/rules/development.md

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

docs/installation.md

@@ -65,22 +65,24 @@ uv tool install --force "remove-ai-watermarks[video,diffusion]"
 
 ## Invisible watermark removal
 
-Diffusion based removal needs the `diffusion` extra:
-
-```bash
-uv tool install --force "remove-ai-watermarks[diffusion]"
-```
-
-The code supports CUDA, XPU, MPS, and CPU devices. A GPU is recommended because
-CPU inference is slow.
-
-For the CUDA only Qwen Image plus Z-Image profile:
+Install the `qwen-zimage` extra:
 
 ```bash
 uv tool install --force "remove-ai-watermarks[qwen-zimage]"
 ```
 
-The `qwen-zimage` extra includes the normal `diffusion` dependencies.
+Both remaining profiles run a Z-Image face stage on the DiffSynth runtime, so
+both need this extra. It includes the `diffusion` dependencies; `diffusion` on its
+own covers the torch and diffusers imports but not the face stage, so it is not
+enough to run a removal.
+
+**An NVIDIA GPU is required.** `qwen-zimage` and `sdxl-zimage` are CUDA-only, and
+construction refuses any other device rather than falling back to a slow or broken
+one. There is no CPU, MPS or XPU path for invisible-watermark removal. Visible-mark
+removal, metadata stripping and every `identify` command still run anywhere.
+
+Video SynthID regeneration is a separate VAE path and does still run on CPU or MPS;
+it needs the `diffusion` extra, not this one.
 
 ## Feature extras
 
@@ -95,10 +97,10 @@ application actually uses:
 | `video` | Visible video identification/removal and timestamp preservation | `visible`, PyAV | No |
 | `detect` | Open DWT-DCT detection for Stable Diffusion, SDXL, and FLUX | `pixels`, PyWavelets | No |
 | `trustmark` | Adobe TrustMark detection | trustmark | Yes |
-| `diffusion` | Diffusion-based invisible watermark removal | `pixels`, Torch, Diffusers | Yes |
+| `diffusion` | Torch and Diffusers runtime; video SynthID regeneration | `pixels`, Torch, Diffusers | Yes |
 | `migan` | MI-GAN ONNX fill backend | `visible`, ONNX Runtime | Model download, no Torch |
 | `lama` | big-LaMa ONNX fill backend | `visible`, ONNX Runtime | Model download, no Torch |
-| `qwen-zimage` | CUDA-only Qwen Image plus Z-Image pipeline | `diffusion`, DiffSynth | Yes |
+| `qwen-zimage` | Invisible image-watermark removal, both CUDA-only profiles | `diffusion`, DiffSynth | Yes |
 | `all` | Every production feature | All rows above | Yes |
 | `dev` | Tests, linting, typing, and upstream parity checks | `visible`, `detect`, upstream invisible-watermark | Yes, for parity tests |
 
@@ -214,5 +216,7 @@ The normal behavior is to skip diffusion when no supported local signal is
 found. A missing signal does not prove that the image is clean. If you know the
 image came from a relevant generator, use `--force`.
 
-If the CLI reports that diffusion dependencies are unavailable, install the
-`diffusion` extra. Video SynthID removal needs both `video` and `diffusion`.
+If the CLI reports that the removal dependencies are unavailable, install the
+`qwen-zimage` extra. `diffusion` alone covers Torch and Diffusers but not the
+DiffSynth face stage that both profiles run. Video SynthID removal is a separate
+path and needs `video` and `diffusion`.