fix(api): derive registered invocation cancellation policy from the executable binding #4185

Problem

Registered HTTP dispatch has a second read/effect classification that disagrees with the existing operation catalog. WorkflowOperation::is_read_only() identifies six read operations, including get/list/history/diff/validate definitions and get-run. Its RegisteredHttpOperation implementation instead returns false unconditionally. The dispatcher chooses cancellation policy using that trait method even after resolving an executable binding with authoritative effect metadata.

This changes behavior: cancellation/deadline handling for a read is routed through authoritative-effect settlement, which can wait for the response grace period or return an indeterminate outcome.

Evidence at reviewed commit 30c23baa1967d4bb04aee3f20deb7a19f302ba61:

• Workflow read operations.
• Trait implementation classifying all Workflow operations as effects.
• Binding lookup followed by the shadow policy decision.
• Different interruption behavior for reads and effects.

Change

Select InvocationCancellationPolicy from the resolved binding.effect().is_read_only(). Remove is_read_only from RegisteredHttpOperation and its per-family implementations. Reuse the binding already needed for route/result validation; do not introduce another registry or policy abstraction.

Review other invocation adapters for the same duplicate classification and migrate any redundant decision at a point where the binding is already available. Keep the change scoped to policy selection and delete obsolete parity-only scaffolding where its separate declaration disappears.

Acceptance criteria

• Workflow read cancellation and deadlines follow the read interruption path after admission.
• Authoritative mutations continue waiting for their durable settlement and expose truthful partial/indeterminate states; cancellation must never turn a committed mutation into an apparent rollback.
• Work and the other registered families derive policy from the same catalog authority.
• Request identity, result-contract validation, scope authorization and existing deadline limits remain intact.
• Focused behavioral coverage exercises one real read interruption and one effect settlement, and fails with the current Workflow trait implementation. Run affected tests through Bazel rather than adding source-string inventories.

Verification and coordination

The classification disagreement and both execution branches were inspected directly; no runtime latency measurement or test execution is claimed. Searches found no duplicate open issue or PR. Merged #4158 changes Work writer jobs and settlement internals; this issue removes an adapter policy disagreement without reopening that storage design.