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/sdk-namespace.test.ts

@@ -0,0 +1,100 @@
+import { describe, test, expect, beforeAll, afterAll } from 'bun:test';
+import { createShade, type Shade } from '@shade/sdk';
+import { createPrekeyServer, MemoryPrekeyStore, PrekeyServerEvents } from '@shade/server';
+import { SubtleCryptoProvider } from '@shade/crypto-web';
+import type { FileEntry } from '../../src/index.js';
+
+const crypto = new SubtleCryptoProvider();
+
+/**
+ * End-to-end test of `Shade.files` — the high-level SDK entrypoint.
+ * Verifies that `shade.files.serve(...)` and `shade.files.client(peer)`
+ * compose correctly and share a single channel + bridges per Shade.
+ */
+describe('Shade.files namespace — end-to-end via SDK getter', () => {
+  let alice: Shade;
+  let bob: Shade;
+  let prekeyServer: { stop(): void };
+  let aliceServer: { stop(): void };
+  let bobServer: { stop(): void };
+  let stopBobFiles: (() => Promise<void>) | null = null;
+
+  beforeAll(async () => {
+    const prekey = createPrekeyServer({
+      crypto,
+      store: new MemoryPrekeyStore(),
+      disableRateLimit: true,
+      events: new PrekeyServerEvents(),
+    });
+    prekeyServer = Bun.serve({ port: 0, fetch: prekey.fetch });
+    const prekeyUrl = `http://localhost:${(prekeyServer as unknown as { port: number }).port}`;
+
+    alice = await createShade({ prekeyServer: prekeyUrl, address: 'alice' });
+    bob = await createShade({ prekeyServer: prekeyUrl, address: 'bob' });
+
+    let aliceUrl = '';
+    let bobUrl = '';
+    alice.configureTransfers({
+      resolveBaseUrl: async (peer) => {
+        if (peer === 'bob') return bobUrl;
+        throw new Error(`unknown peer: ${peer}`);
+      },
+    });
+    bob.configureTransfers({
+      resolveBaseUrl: async (peer) => {
+        if (peer === 'alice') return aliceUrl;
+        throw new Error(`unknown peer: ${peer}`);
+      },
+    });
+    const aliceApp = await alice.transferRoute();
+    const bobApp = await bob.transferRoute();
+    aliceServer = Bun.serve({ port: 0, fetch: aliceApp.fetch });
+    bobServer = Bun.serve({ port: 0, fetch: bobApp.fetch });
+    aliceUrl = `http://localhost:${(aliceServer as unknown as { port: number }).port}`;
+    bobUrl = `http://localhost:${(bobServer as unknown as { port: number }).port}`;
+  });
+
+  afterAll(async () => {
+    if (stopBobFiles !== null) await stopBobFiles();
+    await alice.files.destroy();
+    await bob.files.destroy();
+    await alice.shutdown();
+    await bob.shutdown();
+    aliceServer.stop();
+    bobServer.stop();
+    prekeyServer.stop();
+  });
+
+  test('shade.files getter is memoized', () => {
+    const a = bob.files;
+    const b = bob.files;
+    expect(a).toBe(b);
+  });
+
+  test('serve() + client() round-trip stat through the SDK', async () => {
+    stopBobFiles = await bob.files.serve({
+      stat: async (ctx) => {
+        const e: FileEntry = {
+          name: ctx.path.split('/').filter(Boolean).pop() ?? '',
+          kind: 'file',
+          size: 42,
+          mtime: 1234,
+          metadata: {},
+        };
+        return e;
+      },
+    });
+
+    const fs = await alice.files.client('bob');
+    const result = await fs.stat('/answer.txt');
+    expect(result.name).toBe('answer.txt');
+    expect(result.size).toBe(42);
+    expect(result.mtime).toBe(1234);
+  });
+
+  test('second serve() throws (one handler per Shade)', async () => {
+    await expect(
+      bob.files.serve({ stat: async () => ({ name: 'x', kind: 'file', size: 0, mtime: 0, metadata: {} }) }),
+    ).rejects.toThrow(/handler is already registered/);
+  });
+});