feat(core): add durable mint swap orchestration foundation

[igbopharaoh]

Slice 2 of 6 — orchestration foundation

Summary

• define the durable Mint Swap parent model, exact accounting invariants, prepared-plan
  fingerprint, fenced preparation lease, CAS contract, and operation-event outbox
• add parent-owned mint and melt commands that commit authorization before remote I/O and apply
  results atomically afterward
• split swap-then-melt execution into durable pre-swap and melt authorization phases
• add an optional Mint Swap repository capability with rollback-safe, concurrency-safe memory
  transactions
• add shared adapter contracts for capability absence, CAS, ownership, rollback, due ordering,
  outbox idempotency, and concurrent root writes
• expose the Mint Swap and outbox predicates required by downstream persistent adapters

Current status

• Slice 1 (feat(core): add protocol and secure BOLT11 foundations #400) is merged, and this branch has been realigned with its protocol/security
  foundations
• destination preparation uses the locked quote's persisted NUT-20 key and canonical quote
  accounting
• parent-owned child invariants and legal execution-phase combinations are enforced by shared
  contracts
• the restricted owned-mint remote context preserves custom-handler compatibility
• the latest commit consolidates the adapter predicate exports and makes the polling cadence test
  tolerant of CI runner contention without weakening its cadence assertion
• all current GitHub Actions checks pass

Dependencies and rollout order

The prerequisite for this slice is satisfied by merged PR #400.

The remaining draft slices intentionally target master while retaining an ordered dependency
chain:

1. this PR — Slice 2: orchestration foundation
2. feat(storage): persist mint swap operations #417 — Slice 3: persistent adapters
3. feat(core): coordinate recoverable mint swaps #418 — Slice 4: coordinator and recovery
4. feat(core): add mint swap runtime consumers #419 — Slice 5: runtime consumers
5. feat: activate mint swap v1 #420 — Slice 6: public activation and acceptance

Each downstream PR documents its dependency and should be rebased after the preceding slice merges.

Scope boundaries

• Mint Swap remains dormant in this slice: no Manager/API activation, scheduler, processor,
  history projection, or React surface is added
• persistent SQL and IndexedDB implementations remain in Slice 3
• coordinator and restart recovery remain in Slice 4
• runtime consumers remain in Slice 5
• public activation and acceptance coverage remain in Slice 6
• local research, implementation specifications, acceptance notes, and the architecture
  walkthrough are intentionally excluded from this PR

Verification

• bun run --filter='@cashu/coco-core' typecheck
• bun run --filter='@cashu/coco-adapter-tests' typecheck
• bun run --filter='@cashu/coco-core' build
• bun run --filter='@cashu/coco-adapter-tests' build
• bun run --filter='@cashu/coco-core' test:unit
• bun run test:coverage:core — 1,284 passed
• bun test ./src/test/contract.test.ts from packages/sqlite-bun
• current GitHub Actions: all checks passing

No changeset is included because release metadata is assigned to the final rollout slice.

Closes #366.

[changeset-bot]

⚠️ No Changeset found

Latest commit: 12a6371

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[igbopharaoh]

@codex kindly review

[chatgpt-codex-connector]

Codex Review: Didn't find any major issues. 🚀

Reviewed commit: 12a637183e

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