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/verification-plan.md

@@ -91,20 +91,26 @@ and the ffmpeg audio/video strip. The gap to find is not only
 "logic untested" but
 "never executed on real data", which is precisely what this campaign is for.
 
-#### Bug found by the extension: `--steps` below ~7 crashes inside torch
+#### Bug found by the extension: `--steps` below ~7 crashed inside torch
 
-Effective timesteps are `int(steps * strength)`. At the vendor-adaptive default strength
-(0.15, or 0.10 for OpenAI) any `--steps` under 7 rounds to **zero**, and the pipeline dies
-with a raw traceback:
+**Fixed by deletion.** `--steps` no longer exists, on the CLI or in the Python API,
+so this class of failure is unreachable. Kept as a record of why.
+
+Effective timesteps were `int(steps * strength)`. At the vendor-adaptive default
+strength (0.15, or 0.10 for OpenAI) any `--steps` under 7 rounded to **zero**, and the
+pipeline died with a raw traceback:
 
 ```
-$ remove-ai-watermarks invisible img.png --steps 5
 RuntimeError: cannot reshape tensor of 0 elements into shape [0, -1, 1, 512]
 ```
 
-Fully valid CLI arguments, no special flags, no `--force`. The value is accepted, the
-crash is a torch internal, and nothing tells the user that steps and strength interact.
-Fix is either a clamp to >=1 effective step or an up-front validation naming both values.
+Fully valid CLI arguments, no special flags, no `--force`. The value was accepted, the
+crash was a torch internal, and nothing told the user that steps and strength interact.
+The considered fixes were a clamp to >=1 effective step or an up-front validation
+naming both values; what shipped instead is that each stage owns its own distilled
+schedule and no caller can set it. The general lesson stands: a knob whose valid range
+depends on another knob's value needs the interaction validated where both are known,
+or it needs to not be a knob.
 
 Method note: the first run of the knob rows failed 12 times with this identical error,
 which read like twelve broken features. It was one bad harness parameter (`--steps 4`)