feat: wire accepted kv-unified cache receipts

[antra-tess]

Summary

• compute the immutable tools and system prefix identity for kv-unified compiles
• request caller-owned cache marker mode only when kv-unified is active
• bind each physical provider call to a unique submission and exact wire receipt
• commit presentation and cache state only after that provider call is accepted
• fail or drain outstanding submissions without advancing continuity state
• calibrate context estimates from per-provider-call usage deltas rather than cumulative tool-loop totals
• retain source compatibility with the preceding membrane and context-manager releases while the stacked PRs land

Dependencies:

• feat: add caller-owned cache markers and wire receipts antra-tess/membrane#66
• feat: add the kv-unified context solver context-manager#83

Validation

• npm run build
• targeted kv-unified receipt and usage-accounting tests
• full npm test suite passed

Rollout

No strategy is activated by this PR. Existing agents and marker ownership remain unchanged unless their Context Manager reports kv-unified enabled.

[antra-tess]

agent-framework #139 — ACCEPT at exact head fec2fc430b3da4d7a40e181cff5012eca5c3efa4 (PR base 12f0ee6; origin/main is now 511b722, and git merge --no-commit of that into the head auto-merges with no conflicts). Reviewed as part of the kv-unified package with the lens "does anything change for an agent whose CM is not kv-unified".

Current flows are not disrupted. Gate is isKvUnifiedEnabled() = config.foldingStrategy === 'kv-unified' (CM autobiographical.ts:7445-7447), absent entirely on CM v0.7.0 → false.

Ungated change, evaluated: src/framework.ts:6015-6020 and :6959-6998 compute a per-call usage delta and feed it to reportRealInputTokens for every agent.

• Membrane usage events are cumulative across the native/XML tool loop in both lineages checked (local 8cbbf88 membrane.ts:2489-2500, :3032-3043; release v0.5.81 via turnUsage.addRound, src/utils/usage.ts:119-129), so the premise holds.
• First call: cumulativeDelta(x, 0) = x, byte-identical to base. Retries are a fresh driveStream and a fresh membrane stream, so delta and counter reset together.
• It is a no-op on the value CM consumes: reportRealInputTokens (CM autobiographical.ts:7380-7395) is armed once per compile (:7357) and drops later samples; only the first usage event per compile is consumed and that value is unchanged. agent.lastStream*Tokens and the inference:usage trace still carry cumulative event.usage.

Gated, verified: agent.ts:645-653 calls isKvUnifiedEnabled?.() per activation (trivial); the prefix hash and second buildSystemPrompt (:655-660) run only under kv-unified; cacheMarkers: 'cm-owned' is spread only under kv-unified (:709) so the default request object is identical (test asserts undefined); kvQueue/onCacheWireReceipt (:744-787) only under kv; takeKvSubmission?.() (framework.ts:7000) and the finally drain (:7077-7087) are dead for non-kv agents.

Nonblocking:

• No framework-level test covers the driveStream delta path; the membrane "cumulative event" contract is asserted in a comment only. A driveStream test with two usage events would pin it.
• Comment at framework.ts:6012-6014 says per-call usage feeds kv receipt acceptance; it does not (acceptance keys off takeKvSubmission() per event).
• If a future membrane emitted per-call usage, cumulativeDelta would under-report on calls 2+ whenever current >= previous; unobservable today given the arm-once gate.
• Gated: immutablePrefixHash hashes the input injections' system blocks (agent.ts:652-654) while the wire uses compile's returned systemInjections (:700); CM passes them through unchanged today, nothing pins that. beginKvUnifiedSubmission throws when no draft (CM :7436-7438) from inside membrane's onCacheWireReceipt callback.

Receipts: git diff --check clean; head builds against the deployed Mac membrane/CM (tsc exit 0); against archived release tags membrane v0.5.81 + CM v0.7.0 the head adds zero errors over base (both show the same 3 fixture-artifact TS2322s from two nominal Membrane classes); tests base 635/0/4 → head 639/0/4, failure-set diff empty; mutation (cumulativeDelta → identity) turns the 2 usage-accounting unit tests red; changelog fragment present; version unchanged (0.11.0).