Turn the verified-text fidelity anchor off by default

The whole-frame 15% Qwen-VAE blend returned detector-visible OpenAI
SynthID on poster-scale manifests through the engine text-manifest
path (official Content Provenance API, 2026-08-19: restored detected
x6 with the anchor, clean x6 without it; base outputs clean x6;
pixel-identical stripped controls detected, proving the pixel channel).
Add fidelity_anchor=False to remove_watermark and InvisibleOptions and
--fidelity-anchor on the CLI to reproduce the 0.27.0 research
behavior. Text-box MAE cost of the new default is under one point on
all three fixtures (11.60->11.72, 7.79->7.86, 7.57->8.13).

docs/cli.md

@@ -416,6 +416,12 @@ remove-ai-watermarks invisible image.png -o clean.png \
   --pipeline qwen-zimage --text-manifest verified-lines.json --force
 ```
 
+Since 0.27.1 the global 15% Qwen-VAE fidelity-anchor blend is off by default: it
+was measured to return detector-visible OpenAI SynthID on poster-scale manifests
+(official Content Provenance API, 2026-08-19). `--fidelity-anchor` restores the
+0.27.0 research behavior; text-box fidelity lost by the default is well under one
+MAE point on the measured fixtures.
+
 The manifest is a JSON object with `schema_version: 1`, `verified: true`, decoded
 RGB dimensions, `source_pixel_sha256`, and a non-empty `lines` array. Each line has
 an integer `[x1, y1, x2, y2]` box, exact `text`, a non-empty `script`, and an optional

docs/python-api.md

@@ -614,6 +614,13 @@ postprocessing combinations that were not evaluated. `InvisibleOptions` exposes
 same field for `remove_all`; after a visible-stage edit, the manifest must be built
 against the staged pixels rather than the pristine source.
 
+Since 0.27.1 the mode's global 15% Qwen-VAE fidelity-anchor blend is **off by
+default** (`fidelity_anchor=False`): that whole-frame blend was measured to
+return detector-visible OpenAI SynthID on poster-scale manifests (official
+Content Provenance API, 2026-08-19 - detected x6 with the anchor, clean x6
+without it, controls and base outputs validated in the same sessions). Pass
+`fidelity_anchor=True` to reproduce the 0.27.0 research behavior.
+
 `remove_watermark` takes strength, seed, tiling, resolution, and postprocessing
 controls. It takes no model id, step count or guidance scale, and neither does the
 constructor: each profile pins its model stack, its per-stage schedule and CFG

docs/text-protection-research.md

@@ -343,3 +343,29 @@ The stable errors were punctuation: one lost English comma and an ideographic
 comma consistently replaced by ASCII. Thus crop agreement and confidence do
 not verify literal text. The helper is retained only to seed annotations; every
 proposal needs manual review before it can enter the restoration compositor.
+
+## Production-path anchor leak and fix (2026-08-19)
+
+The engine `text_manifest=` path (unlike the research compositor above) blends a
+15% Qwen-VAE fidelity anchor across the WHOLE frame before glyph restoration.
+Certified through the official OpenAI Content Provenance API on the exact
+production path (qwen-zimage, seed 0, no strength override, untiled, LANCZOS
+resize-back, metadata strip; library 0.27.0 @ 50d9f448):
+
+- controls (pixel-identical metadata-stripped sources): `synthid: detected` -
+  the pixel channel was proven live before every session;
+- base outputs: `clean` x6 (two 20-line posters, 3 attempts each);
+- text-restored WITH the anchor: `synthid: detected` x6, deterministic;
+- text-restored with `FIDELITY_BLEND_ALPHA = 0` (runtime ablation, base bytes
+  identical between runs): `clean` x6.
+
+The anchor was therefore the leak channel: a 15% global donor admixture over a
+scrubbed frame returns enough OpenAI SynthID for the provider detector. Fidelity
+cost of dropping it (source-referenced text-box MAE): 11.60->11.72, 7.79->7.86,
+and 7.57->8.13 across the two posters and the CJK sign - well under one point
+against base MAEs of 24.7/16.8/10.2. Since 0.27.1 the anchor is off by default
+(`fidelity_anchor` parameter on `remove_watermark` / `InvisibleOptions` /
+`--fidelity-anchor`); Google rows were not re-queried because the default
+strength leaves that fixture's base detected (the vendor-strength lane tracks
+that separately). Certification artifacts: raiw-app
+`data/certification/text-restoration-2026-08-19-A1/` (sha256-stamped rows).