v0.25.1 - Cross-Platform Receipt Integrity

Agent Memory Bridge 0.25.1 is a narrow correctness patch for Trustworthy
Adaptive Retrieval. It does not change the 13-tool MCP surface or schema v5.

What changed

• Recall receipt decoding now rejects non-canonical base64url aliases, including
  encodings that decode to the same signature bytes.
• Receipt tamper tests now mutate signature bytes deterministically and cover
  non-canonical payload and signature forms.
• The command-provider test gateway consumes stdin before early output or exit,
  removing a Windows Python 3.11 pipe race that could mask the intended provider
  error.
• Test command construction now uses the same POSIX-style argv quoting expected
  by the production command parser.

Validation snapshot

• pytest --collect-only -q tests: 604 tests collected
• Full isolated suite: 601 pass, 3 skip
• Focused receipt tests: 23 pass
• Repeated Windows Python 3.11 command-provider regression: 25 pass
• Release contract, public-surface, onboarding, lint, format, and typing gates
  pass locally.

Boundaries

This patch does not add active feedback reranking, authenticated callers,
namespace ACLs, ANN retrieval, graph memory, automatic policy, hosted identity,
or multi-user infrastructure. Feedback remains append-only, receipt-bound,
redacted, and shadow-only.