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>

examples/07-streams-upload/alice-sender.ts

@@ -0,0 +1,54 @@
+/**
+ * Alice — sender. Uploads a local file to Bob using 4 parallel lanes,
+ * 1 MiB chunks, and the default HTTP transport. Prints sender-side
+ * progress + the verified sha256 on completion.
+ *
+ * Usage:
+ *   bun run examples/07-streams-upload/alice-sender.ts <path/to/file>
+ */
+import { readFile } from 'node:fs/promises';
+import { basename } from 'node:path';
+import { createShade } from '@shade/sdk';
+
+const PREKEY_URL = 'http://localhost:9991';
+const BOB_BASE_URL = 'http://localhost:9992';
+
+const filePath = process.argv[2];
+if (filePath === undefined || filePath === '') {
+  console.error('usage: alice-sender.ts <path/to/file>');
+  process.exit(2);
+}
+
+const bytes = await readFile(filePath);
+const name = basename(filePath);
+
+const alice = await createShade({ prekeyServer: PREKEY_URL, address: 'alice' });
+
+alice.configureTransfers({
+  resolveBaseUrl: async (peer) => {
+    if (peer === 'bob') return BOB_BASE_URL;
+    throw new Error(`unknown peer ${peer}`);
+  },
+});
+
+console.log(`[alice] uploading ${name} (${bytes.length} bytes) → bob`);
+
+const handle = await alice.upload({
+  to: 'bob',
+  input: new Uint8Array(bytes),
+  lanes: 4,
+  chunkSize: 1024 * 1024,
+  metadata: { name },
+  onProgress: (p) => {
+    const pct = p.percent !== undefined ? `${(p.percent * 100).toFixed(1)}%` : '—';
+    const mbps = (p.bytesPerSecond / (1024 * 1024)).toFixed(2);
+    process.stdout.write(`\r[alice] ${pct}   ${mbps} MB/s   ${p.bytesSent}/${p.bytesTotal ?? '?'} B`);
+  },
+});
+
+const result = await handle.done();
+process.stdout.write('\n');
+console.log(`[alice] done — ${result.bytesSent} B in ${result.durationMs.toFixed(0)} ms`);
+console.log(`[alice] sha256 = ${result.sha256}`);
+
+await alice.shutdown();