feat(files): @shade/files 0.3.0 — E2EE filesystem RPC primitive

M-Files-1..6 land the full files-RPC layer + everything 0.3.0 needs to
ship. Apps keep their own UI; this layer ships the typed RPC, the
streams bridge for content I/O, and production hooks (rate limit,
retention, fingerprint gate, metrics).

@shade/files (NEW)
- Standard ops: list/stat/mkdir/delete/move/read/write/getThumbnail with
  Zod-validated wire schemas + clean user-handler types.
- Custom ops: typed via TypeScript declaration merging on CustomOpsMap
  + per-op Zod schemas; client.custom('app.foo', {...}) is fully typed.
- Content I/O: inline (≤ 256 KiB plaintext) base64-in-RPC; streams
  (> 256 KiB) ride @shade/transfer via userMetadata.shadeFilesWriteId
  / shadeFilesReadStreamId correlation. Server-side TransformStream
  bridges accept inbound transfers immediately (engine rejects chunks
  that arrive before accept) and park the readable for the matching
  RPC.
- Directory ops: walk(path, opts) async-iterable depth-first walker;
  uploadDirectory()/downloadDirectory() with bounded concurrency pool
  (default 4, cap 16), aggregated progress, abort.
- Production hooks (callback-based, vendor-neutral): rate-limit (op +
  byte), idempotency cache (LRU + TTL + in-flight de-dupe), path
  policy (traversal + percent-decode hardening), fingerprint gate
  (required/optional/reject), pluggable Ed25519 sig verification with
  ±5 min replay window, onMetric sink (standard names).
- React hooks (subpath @shade/files/react): ShadeFilesProvider,
  useShadeFiles, useFileList, useFileTransfer/Upload/Download.
- Shade.files.serve(handler) + Shade.files.client(peer) high-level
  entrypoint in @shade/sdk; lazy + memoized; one handler per Shade.

Wire format bump
- @shade/proto wire VERSION 0x01 → 0x02. Length prefixes changed from
  u16 to u32. The previous u16 silently truncated payloads above
  64 KiB — a hard correctness ceiling that blocked inline file ops
  up to 256 KiB. Wire-incompatible with 0.2.x peers; new sessions
  only. Cross-platform Kotlin port (android/shade-android) updated to
  match; test-vectors/wire-format.json regenerated.

Concurrency safety
- ShadeSessionManager.encrypt/.decrypt now run under per-peer mutex.
  Concurrent decryptions of the same peer raced ratchet state
  (manifested as sporadic "Failed to decrypt — wrong key or tampered
  data" under load — surfaced once concurrent uploadDirectory pumped
  many writes in flight). Encrypt was already serialized via
  Shade.send's encryptChains; decrypt is now serialized at the
  manager layer too.

@shade/streams extension
- StreamMetadata.userMetadata?: Record<string, string> for
  application-level key/value pairs that round-trip verbatim through
  stream-init plaintext. Used by @shade/files for write/read
  correlation; available to any consumer.

@shade/sdk extension
- Shade.files getter (lazy + memoized).
- BackgroundHooks.onPruneFiles + periodic timer (default 5 min) +
  BackgroundTasks.setHook(name, fn) for runtime hook registration.

Bundles in-flight 0.2.0 work
- packages/shade-streams/, packages/shade-transfer/, related
  shade-sdk streams-bridge + shade-widgets transfer hooks were
  uncommitted prior to this session. Including them keeps the
  workspace consistent at 0.3.0 since @shade/files depends on them.

Tests
- 74 new tests in @shade/files (572 → 646 workspace pass; 0 fail;
  3× stable). Coverage spans unit (inline-threshold + concurrency),
  integration (read-write inline + streams up to 1 MiB, walk +
  upload/download directory, custom-op, metrics, SDK namespace
  end-to-end), and security (tampered-envelope sig verification,
  replay window, fingerprint gate, rate-limit + quota).

Release artifacts
- All packages bumped to 0.3.0 via scripts/bump-version.ts.
- scripts/publish-all.ts PACKAGES updated with shade-files in
  topological order (after shade-transfer, before shade-sdk).
- bun run publish:dry clean (14 packed, 0 failed).
- examples/08-files-browser/ — three-process CLI demo (prekey + Bob
  server + Alice CLI) covering list/stat/mkdir/delete/upload/download.
- docs/files.md — full API + design doc.
- CHANGELOG.md 0.3.0 entry.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

packages/shade-files/tests/unit/envelope-codec.test.ts

@@ -0,0 +1,149 @@
+import { describe, test, expect } from 'bun:test';
+import {
+  encodeEnvelope,
+  looksLikeFileEnvelope,
+  tryParseEnvelope,
+  classify,
+  KIND_LIST_V1,
+  KIND_ERROR_V1,
+  KIND_CANCEL_V1,
+  responseKindOf,
+} from '../../src/index.js';
+import type { RpcRequest, RpcResponse, RpcError, RpcCancel } from '../../src/index.js';
+
+const ID = 'AbCdEfGhIjKlMnOpQrStUv';
+
+describe('looksLikeFileEnvelope', () => {
+  test('matches plaintext containing shade.fs', () => {
+    expect(looksLikeFileEnvelope('{"kind":"shade.fs.list/v1"}')).toBe(true);
+  });
+  test('rejects unrelated', () => {
+    expect(looksLikeFileEnvelope('hello world')).toBe(false);
+    expect(looksLikeFileEnvelope('{"kind":"shade.stream-init/v1"}')).toBe(false);
+  });
+});
+
+describe('tryParseEnvelope', () => {
+  test('returns null on non-JSON', () => {
+    expect(tryParseEnvelope('not json {{')).toBeNull();
+  });
+
+  test('returns null on JSON that does not match any envelope', () => {
+    expect(tryParseEnvelope('{"kind":"unknown"}')).toBeNull();
+    expect(tryParseEnvelope('{"foo":"bar"}')).toBeNull();
+  });
+
+  test('classifies request', () => {
+    const req: RpcRequest = {
+      kind: KIND_LIST_V1,
+      id: ID,
+      args: { path: '/' },
+      sig: 'abc',
+      signedAt: 1,
+    };
+    const c = tryParseEnvelope(encodeEnvelope(req));
+    expect(c?.kind).toBe('request');
+  });
+
+  test('classifies response', () => {
+    const resp: RpcResponse = {
+      kind: responseKindOf(KIND_LIST_V1),
+      id: ID,
+      result: { entries: [], hasMore: false },
+    };
+    const c = tryParseEnvelope(encodeEnvelope(resp));
+    expect(c?.kind).toBe('response');
+  });
+
+  test('classifies error', () => {
+    const err: RpcError = {
+      kind: KIND_ERROR_V1,
+      id: ID,
+      error: { code: 'NOT_FOUND', message: 'missing' },
+    };
+    const c = tryParseEnvelope(encodeEnvelope(err));
+    expect(c?.kind).toBe('error');
+  });
+
+  test('classifies cancel', () => {
+    const cancel: RpcCancel = {
+      kind: KIND_CANCEL_V1,
+      id: ID,
+      reason: 'user-cancel',
+    };
+    const c = tryParseEnvelope(encodeEnvelope(cancel));
+    expect(c?.kind).toBe('cancel');
+  });
+
+  test('rejects request with missing fields', () => {
+    expect(tryParseEnvelope(JSON.stringify({ kind: KIND_LIST_V1 }))).toBeNull();
+    expect(
+      tryParseEnvelope(
+        JSON.stringify({ kind: KIND_LIST_V1, id: ID, args: {}, sig: 'x' }),
+      ),
+    ).toBeNull(); // missing signedAt
+  });
+
+  test('rejects response shape with non-.response suffix and no signature', () => {
+    // Missing both `.response` suffix (so not a response) AND missing
+    // `sig`/`signedAt` (so not a valid request) → no schema matches.
+    expect(
+      tryParseEnvelope(
+        JSON.stringify({ kind: 'shade.fs.list/v1', id: ID, result: {} }),
+      ),
+    ).toBeNull();
+  });
+
+  test('rejects malformed id length', () => {
+    const req = {
+      kind: KIND_LIST_V1,
+      id: 'short',
+      args: {},
+      sig: 'x',
+      signedAt: 1,
+    };
+    expect(tryParseEnvelope(JSON.stringify(req))).toBeNull();
+  });
+});
+
+describe('classify on already-validated envelopes', () => {
+  test('correct discriminator on each branch', () => {
+    const req: RpcRequest = {
+      kind: KIND_LIST_V1, id: ID, args: {}, sig: 'x', signedAt: 1,
+    };
+    expect(classify(req).kind).toBe('request');
+
+    const resp: RpcResponse = {
+      kind: responseKindOf(KIND_LIST_V1), id: ID, result: {},
+    };
+    expect(classify(resp).kind).toBe('response');
+
+    const err: RpcError = {
+      kind: KIND_ERROR_V1, id: ID, error: { code: 'NOT_FOUND', message: '' },
+    };
+    expect(classify(err).kind).toBe('error');
+
+    const cancel: RpcCancel = { kind: KIND_CANCEL_V1, id: ID };
+    expect(classify(cancel).kind).toBe('cancel');
+  });
+});
+
+describe('encodeEnvelope', () => {
+  test('roundtrips request envelope', () => {
+    const req: RpcRequest = {
+      kind: KIND_LIST_V1,
+      id: ID,
+      args: { path: '/foo' },
+      idempotencyKey: 'IdemKeyAaBbCcDdEeFfGgH',
+      attempt: 1,
+      sig: 'sig',
+      signedAt: 1730000000000,
+    };
+    const c = tryParseEnvelope(encodeEnvelope(req));
+    expect(c?.kind).toBe('request');
+    if (c?.kind === 'request') {
+      expect(c.envelope.idempotencyKey).toBe('IdemKeyAaBbCcDdEeFfGgH');
+      expect(c.envelope.attempt).toBe(1);
+    }
+  });
+});