Align Decision vocabulary to the Agent Control Standard

[open-coder-ai]

What this changes

Renames the canonical Decision outcomes to match the Agent Control Standard's verdict
names: ASK -> ESCALATE, REWRITE -> TRANSFORM. The old names and
Decision.ask()/Decision.rewrite() remain as deprecated aliases bound to the same
strings, so every existing is/== comparison and Decision("ask"/"rewrite", ...) call
keeps working (the deprecated classmethods now emit DeprecationWarning). Adds WARN
(ACS warn), which degrades to a plain, honestly-labelled allow via a new
allow_semantics.WARN_SPEAKS (starts empty -- no adapter's warning channel is
established yet), the same shape vouch already gets on ten of twelve adapted agents.
vouch itself is unchanged -- ACS's closed verdict set cannot express it, so ACS becomes
the thirteenth surface it degrades to allow on. pre_model_call/post_model_call are
not adopted (no adapted agent exposes either hook yet; see
plan/acs-alignment-and-delegation.md §1.5 in org-plan).

matrix.capability() now returns both a "rewrite" and a "transform" key (same value)
for one minor version; can_transform() joins can_rewrite(). degraded_from now reports
the canonical ACS spelling ("transform") -- a real, called-out break, since it is a value
inside evidence, not a name. Both VOUCH and WARN are now exported from the package top
level, fixing the pre-existing asymmetry where VOUCH was reachable only via
agentseam.contract.VOUCH.

The wire never moves. No vendor dialect word changes: adapters still speak each
vendor's own ask/rewrite/etc. exactly as before. W34's golden fixture replay suite
(tests/test_golden_fixtures.py + tests/fixtures/golden/) passes byte-for-byte
unchanged, not regenerated -- the proof that this is a rename of agentseam's own
vocabulary, not a wire change. Recounted the zero-literal-comparison claim from W17: still
zero == "ask"-style literal comparisons in src/agentseam/adapters/, all via imported
constants.

Docs (README.md, llms.txt, ARCHITECTURE.md, AGENTS.md), the generated vendor
example pages (examples/generate.py + examples/generated/), and the derived
docs/assets/social-preview.svg/.png brand card are updated to match. Added a
CHANGELOG.md Unreleased entry; no version bump.

Claim check

• No capability claim is widened without a mechanism behind it (the "transform" key
  mirrors the existing "rewrite" value; no MATRIX row's boolean values changed)
• No new/changed MATRIX row — not applicable
• No new payload shapes — not applicable

Checks

• pytest -q passes (1234 passed, 4 skipped)
• ruff check . and ruff format --check . pass
• Runtime path is still stdlib-only (no new imports outside the standard library --
  contract.py adds import warnings, which is stdlib)
• Commits are signed off (git commit -s)
• python examples/generate.py --check passes
• python docs/assets/gen_brand_assets.py --check passes (regenerated; required CI job)
• Golden fixture suite passes with tests/fixtures/golden/ untouched (git diff shows
  no changes to that directory)

Notes for the reviewer

docs/assets/gen_brand_assets.py's decision_outcomes() and examples/generate.py's
DECISIONS list both filter out Decision.DEPRECATED_ALIASES (ask, rewrite) — otherwise
each would try to treat the deprecated aliases as distinct outcomes and either assert-fail
(brand assets: ASK no longer equals "ask") or duplicate a page section for an outcome
that produces identical output to its canonical counterpart.

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Generated by Claude Code