refactor(storage): add SQLite context offload foundation - #4078

Summary

• Define the durable Session context reference, typed owner identities, whole-object byte caps, quota inputs, and async context-offload Store contract.
• Add a dedicated versioned SQLite authority with WAL, FULL synchronous durability, foreign keys, incremental auto-vacuum, content-addressed BLOBs, typed Session references, and transactionally maintained usage counters.
• Implement atomic and idempotent put, Session-authorized whole-object read with SHA-256 verification, reference release, logical/physical quota enforcement, and fail-closed schema validation.

This is the storage-only first slice of #4071. It is intentionally not wired to Read image, Tool Result archives, StorageRef, Session copy/retirement, GC, or legacy migration yet, so it does not change production behavior.

Refs #4071

Verification

• npm --workspace @maka/core run build
• npm --workspace @maka/storage run build
• NODE_NO_WARNINGS=1 node --test packages/storage/dist/__tests__/sqlite-context-offload-store.test.js — 11/11 pass
• NODE_NO_WARNINGS=1 node --test --test-reporter=dot "packages/storage/dist/**/*.test.js" — full storage suite passes
• npx biome lint on all changed TypeScript files
• npm run check:asf-headers

Node 22 emits an experimental node:sqlite warning. Without NODE_NO_WARNINGS=1, one existing child-process fixture treats that warning as stderr failure; the fixture passes 5/5 with the warning disabled.

Follow-up slices

• Add the authenticated Storage Root facade and freeze measured Session/workspace product quotas.
• Add bounded copy, Session retirement, GC, checkpoint, vacuum, and backup operations.
• Route Read image snapshots and Tool Result archives through typed facades.
• Add post-Ready legacy migration and retire replay use of ArtifactStore.

AI use

• No generative tool made a substantive contribution
• Generative tooling made a substantive contribution

Tool(s) and scope: OpenAI Codex contributed repository inspection, interface/schema design, implementation, tests, and PR text. The commit includes the required Generated-by trailer.

Checklist

• Tests cover the change and fail without it
• Lint, format, typecheck and the affected suites pass locally

Does this PR entail a change in behavior?

• Yes — described under Summary above
• No