Tasks — Enterprise hardening (resilience cluster) for `@suaveplan/packer`

1. Spec authoring

1.1 Read ../suaveplan/enterprise/packer.md end-to-end
1.2 Read openspec/specs/packer/spec.md
1.3 Read openspec/AGENTS.md Sections 13 and 14
1.4 Draft proposal.md from openspec/templates/proposal.md
1.5 Fill in ## Source mapping table — every requirement cites a line range
1.6 Draft specs/packer/spec.md from openspec/templates/spec-delta.md
1.7 Every requirement in the spec delta carries a **Verified by:** line naming concrete it(...) titles

2.1 New src/runtime/runtime.ts — defaultClock, defaultMonotonicClock, defaultRng, resolveRuntime(opts) returning { clock, monotonicClock, rng }.
2.2 Sibling .md, .types.ts, index.ts barrel.
2.3 Extend PackerOptions, PackChunkedOptions, UnpackChunkedOptions with clock?: Clock, monotonicClock?: MonotonicClock, rng?: Rng.

3.1 Add @suaveplan/retry to packer/package.json deps (workspace:^).
3.2 New src/retry/retryable-read.ts — retryRead(reader, opts) wrapping reader.read() in withRetry.
3.3 Extend normalizeSource to accept retryConfig? and route ReadableStream reads through retryRead.
3.4 Extend AbstractPacker.packStream's collect helper to accept and propagate retryConfig? to normalizeSource.
3.5 Thread retryConfig? and signal? through PackerOptions, PackChunkedOptions, UnpackChunkedOptions.

4.1 Add @suaveplan/idempotency to packer/package.json deps (workspace:^).
4.2 New src/idempotency/idempotency.ts — PackIdempotencyGuard consuming IdempotencyStoreAdapter, computing content-derived dedup key.
4.3 Sibling .md, .types.ts, index.ts barrel.
4.4 Add idempotency?: { store, ttlMs?, enabled? } to PackerOptions.
4.5 Packer.pack short-circuits on cache hit before any pipeline work; populates store on miss.

5.1 Add signal?: AbortSignal to UnpackOptions.
5.2 Add PackOptions interface ({ filename?, signal? }) on types/packer.types.ts.
5.3 Overload Packer.pack(data, filenameOrOpts?, opts?) accepting either filename string or PackOptions.
5.4 Unpacker.unpack checks signal.aborted at every yield point (5 places).
5.5 Packer.pack checks signal.aborted at every yield point (5 places).
5.6 packChunks checks signal.aborted between emitted chunks.
5.7 New i18n catalog keys packer.error.ABORTED.pack, packer.error.ABORTED.pack-chunks.

6.1 AbstractPacker.buildMetadata reads timestamp from this.options.clock.
6.2 packer/packer.ts randomBytes replaced with this.options.rng.nextBytes(n).
6.3 All nowMs() helpers across the package route through this.options.monotonicClock (or resolved per-call for chunked async fns).
6.4 Grep verify: zero Date.now\|Math.random\|crypto.getRandomValues\|performance.now outside src/runtime/runtime.ts.

7.1 src/runtime/runtime.test.ts + .spec-conformance.test.ts — pins defaults; grep audit.
7.2 src/retry/retryable-read.test.ts + .spec-conformance.test.ts — pins retry attempts, abort mid-backoff, default single-attempt.
7.3 src/idempotency/idempotency.test.ts + .spec-conformance.test.ts — pins hit / miss / disabled / custom store.
7.4 src/packer/packer.spec-conformance.test.ts extended — abort, idempotency, clock, rng, determinism, legacy overload.
7.5 src/unpacker/unpacker.spec-conformance.test.ts extended — pre-flight abort, mid-pipeline abort.
7.6 src/chunked/packer/packer.spec-conformance.test.ts extended — mid-stream abort.
7.7 Every it(...) carries { timeout: 5000 } (or 30000 for async I/O).

8.1 Sibling .md for every new implementation .ts (≥200 words, basic + advanced examples).
8.2 Update README.md Modules list with retry/, idempotency/, runtime/.

10.1 bunx turbo lint typecheck test --filter=@suaveplan/drive-plugin-chunks --filter=@suaveplan/drive-webrtc — green.

11.1 Generics threaded; expectTypeOf assertions on every literal-type claim.
11.2 Zod schemas wired at every declared boundary.
11.3 Every error code in error-codes.ts thrown by at least one production path.
11.4 OTel instruments emitted from production paths and asserted with a real in-memory MeterProvider (NO vi.mock).
11.5 No export * in feature barrels.
11.6 No direct vitest / bun:test imports.
11.7 No retroactive tick — every box above reflects work done in this change.
11.8 Sibling .md for every new .ts.
11.9 Items R-1, R-2, R-3, R-4 each have ≥1 production code path and ≥1 test pinning every named scenario.

12.1 Fold specs/packer/spec.md into openspec/specs/packer/spec.md.
12.2 Move openspec/changes/enterprise-packer-resilience/ → openspec/archive/<yyyy-mm-dd>-enterprise-packer-resilience/.
12.3 Refresh MANIFEST.md.