Read the InvisMark soft-binding algorithm and its signed watermark id

Reachable c2pa.soft-binding assertions now surface their exact alg and the
bounded printable block value next to the normalized vendor label; a value
without its algorithm stays hidden because it cannot be attributed.
com.microsoft.invismark.1 uses that value as the pixel-watermark identifier
in Microsoft Paint output, so identify names it, metadata carries it, and an
InvisMark soft binding keeps the invisible-removal gate fail-safe even after
C2PA asset binding goes invalid. Content fingerprints still do not trigger
pixel regeneration. Removal is verified against Microsoft's Content
Provenance Detection API, which reports Watermark and C2PA separately; the
protocol and the pixel-identical control requirement are documented.

Implemented in a parallel session; verified, gated, and committed by pi.

pre-commit: 1) maintain.sh - exit 1 on the known uv-secure lightning PYSEC-2026-3624 triage (no fix available, unchanged from 0.29.0); ruff, pyright src/, and 1391 tests passed separately; 2) /simplify - single-pass, clean; 3) docs sync - five docs updated by the author session, no remaining references found; 4) CLAUDE.md - invariants recorded in module-internals, no change needed

docs/module-internals.md

@@ -392,6 +392,15 @@ manifest names only `c2pa-tool` while a validated ingredient names Dreamina, and
 Firefly chains that identify `Adobe_Firefly` without repeating a digital source
 type. Unreachable manifests remain excluded.
 
+Reachable `c2pa.soft-binding*` assertions retain their exact `alg` and bounded,
+printable block `value` in addition to the normalized vendor label. A block value
+without its algorithm is not surfaced because it cannot be attributed to a
+decoder or registry entry. `com.microsoft.invismark.1` uses that value as the
+pixel-watermark identifier in Microsoft Paint output. An InvisMark soft binding
+keeps the invisible-removal gate fail-safe even when the C2PA asset binding has
+since become invalid, because metadata damage does not prove the pixel carrier
+disappeared. Content-fingerprint soft bindings do not trigger pixel regeneration.
+
 The SDK default enables trust verification but supplies no production trust
 anchors. Consequently, an installation without an explicitly maintained C2PA
 trust bundle reports otherwise valid signer chains as untrusted and keeps their