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/integration/walk.test.ts

@@ -0,0 +1,126 @@
+import { describe, test, expect, beforeAll, afterAll } from 'bun:test';
+import { walk, type FileEntry, NotFoundError } from '../../src/index.js';
+import { setupFileRig, type FileTestRig } from './helpers/rig.js';
+
+describe('walk — async-iterable depth-first directory traversal', () => {
+  let rig: FileTestRig;
+  // In-memory tree:
+  //   /
+  //   ├── a/
+  //   │   ├── 1.txt
+  //   │   └── b/
+  //   │       └── 2.txt
+  //   ├── c/
+  //   │   └── 3.txt
+  //   └── 4.txt
+  const tree = new Map<string, FileEntry>();
+
+  function setEntry(path: string, kind: 'file' | 'dir'): void {
+    const name = path === '/' ? '' : path.split('/').filter(Boolean).pop() ?? '';
+    tree.set(path, { name, kind, size: kind === 'file' ? 10 : 0, mtime: 0, metadata: {} });
+  }
+
+  beforeAll(async () => {
+    tree.clear();
+    setEntry('/', 'dir');
+    setEntry('/a', 'dir');
+    setEntry('/a/1.txt', 'file');
+    setEntry('/a/b', 'dir');
+    setEntry('/a/b/2.txt', 'file');
+    setEntry('/c', 'dir');
+    setEntry('/c/3.txt', 'file');
+    setEntry('/4.txt', 'file');
+
+    rig = await setupFileRig({
+      list: async (ctx) => {
+        if (!tree.has(ctx.path)) throw new NotFoundError(ctx.path);
+        const entries: FileEntry[] = [];
+        for (const [path, entry] of tree) {
+          if (path === ctx.path) continue;
+          if (!path.startsWith(ctx.path === '/' ? '/' : ctx.path + '/')) continue;
+          const rest = path.slice(ctx.path === '/' ? 1 : ctx.path.length + 1);
+          if (rest.includes('/')) continue;
+          entries.push(entry);
+        }
+        return { entries, hasMore: false };
+      },
+    });
+  });
+
+  afterAll(async () => {
+    await rig.teardown();
+  });
+
+  test('walks the entire tree depth-first', async () => {
+    const items: { path: string; depth: number }[] = [];
+    for await (const item of walk(rig.fs, '/')) {
+      items.push({ path: item.relativePath, depth: item.depth });
+    }
+    // Depth-first order: visit a, then descend into a/* (1.txt + a/b → a/b/2.txt), then c, c/3.txt, then 4.txt
+    expect(items.map((i) => i.path)).toEqual([
+      'a',
+      'a/1.txt',
+      'a/b',
+      'a/b/2.txt',
+      'c',
+      'c/3.txt',
+      '4.txt',
+    ]);
+    // Depth values
+    expect(items.find((i) => i.path === 'a')?.depth).toBe(1);
+    expect(items.find((i) => i.path === 'a/1.txt')?.depth).toBe(2);
+    expect(items.find((i) => i.path === 'a/b/2.txt')?.depth).toBe(3);
+  });
+
+  test('respects maxDepth', async () => {
+    const items: string[] = [];
+    for await (const item of walk(rig.fs, '/', { maxDepth: 1 })) {
+      items.push(item.relativePath);
+    }
+    // Only direct children — no descent into /a or /c.
+    expect(items.sort()).toEqual(['4.txt', 'a', 'c']);
+  });
+
+  test('breaks cleanly when consumer stops iterating', async () => {
+    const items: string[] = [];
+    for await (const item of walk(rig.fs, '/')) {
+      items.push(item.relativePath);
+      if (items.length === 2) break;
+    }
+    expect(items).toEqual(['a', 'a/1.txt']);
+  });
+
+  test('filter callback skips entries (and excludes their subtree)', async () => {
+    const items: string[] = [];
+    for await (const item of walk(rig.fs, '/', {
+      filter: (entry, _rel) => entry.name !== 'a',
+    })) {
+      items.push(item.relativePath);
+    }
+    expect(items.sort()).toEqual(['4.txt', 'c', 'c/3.txt']);
+  });
+
+  test('aborts via signal mid-walk', async () => {
+    const ctrl = new AbortController();
+    const items: string[] = [];
+    setTimeout(() => ctrl.abort(), 5);
+    let threw = false;
+    try {
+      for await (const item of walk(rig.fs, '/', { signal: ctrl.signal })) {
+        items.push(item.relativePath);
+        await new Promise((r) => setTimeout(r, 10));
+      }
+    } catch {
+      threw = true;
+    }
+    expect(threw).toBe(true);
+  });
+
+  test('walking non-existent path → throws on first list', async () => {
+    await expect(async () => {
+      for await (const _item of walk(rig.fs, '/nope')) {
+        /* unreachable */
+      }
+    }).toThrow();
+  });
+});