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-transfer/src/receiver/output.ts

@@ -0,0 +1,166 @@
+import type { TransferOutput } from '../types.js';
+
+/**
+ * Generic chunk sink. The orchestrator writes plaintext chunks IN ORIGINAL
+ * BYTE ORDER, then calls `finalize()`. `toBytes()` is only valid for
+ * `'buffer'` sinks.
+ */
+export interface OutputSink {
+  write(chunk: Uint8Array): Promise<void>;
+  finalize(): Promise<void>;
+  abort(reason?: string): Promise<void>;
+  toBytes(): Uint8Array | null;
+}
+
+/**
+ * Adapter from a `TransferOutput` (consumer-supplied) to an `OutputSink`.
+ *
+ * The `'file'` sink is Bun-specific (uses `Bun.file(path).writer()`) — for
+ * Node use a `'pipe'` sink with an `fs.createWriteStream`.
+ */
+export async function resolveOutputSink(out: TransferOutput): Promise<OutputSink> {
+  switch (out.kind) {
+    case 'pipe':
+      return createPipeSink(out.pipeTo);
+    case 'callback':
+      return createCallbackSink(out.onChunk);
+    case 'buffer':
+      return createBufferSink();
+    case 'file':
+      return createBunFileSink(out.path);
+    case 'fileHandle':
+      return createFileHandleSink(out.handle);
+  }
+}
+
+function createPipeSink(stream: WritableStream<Uint8Array>): OutputSink {
+  const writer = stream.getWriter();
+  return {
+    async write(chunk) {
+      await writer.write(chunk);
+    },
+    async finalize() {
+      try {
+        await writer.close();
+      } finally {
+        writer.releaseLock?.();
+      }
+    },
+    async abort(reason) {
+      try {
+        await writer.abort(reason);
+      } catch {
+        /* swallow */
+      } finally {
+        writer.releaseLock?.();
+      }
+    },
+    toBytes() {
+      return null;
+    },
+  };
+}
+
+function createCallbackSink(
+  onChunk: (chunk: Uint8Array) => void | Promise<void>,
+): OutputSink {
+  return {
+    async write(chunk) {
+      await onChunk(chunk);
+    },
+    async finalize() {
+      /* no-op */
+    },
+    async abort() {
+      /* no-op */
+    },
+    toBytes() {
+      return null;
+    },
+  };
+}
+
+function createBufferSink(): OutputSink {
+  const parts: Uint8Array[] = [];
+  let totalLen = 0;
+  return {
+    async write(chunk) {
+      parts.push(chunk);
+      totalLen += chunk.length;
+    },
+    async finalize() {
+      /* no-op */
+    },
+    async abort() {
+      parts.length = 0;
+      totalLen = 0;
+    },
+    toBytes() {
+      const out = new Uint8Array(totalLen);
+      let off = 0;
+      for (const p of parts) {
+        out.set(p, off);
+        off += p.length;
+      }
+      return out;
+    },
+  };
+}
+
+async function createBunFileSink(path: string): Promise<OutputSink> {
+  // Lazy import so non-Bun runtimes don't fail at import time.
+  const bunGlobal = (globalThis as unknown as { Bun?: { file: (p: string) => { writer: () => unknown } } })
+    .Bun;
+  if (bunGlobal === undefined) {
+    throw new Error("'file' output sink requires Bun runtime");
+  }
+  const writer = bunGlobal.file(path).writer() as {
+    write: (chunk: Uint8Array) => number | Promise<number>;
+    end: () => Promise<number> | number;
+    flush: () => Promise<number> | number;
+  };
+  return {
+    async write(chunk) {
+      await Promise.resolve(writer.write(chunk));
+    },
+    async finalize() {
+      await Promise.resolve(writer.flush());
+      await Promise.resolve(writer.end());
+    },
+    async abort() {
+      try {
+        await Promise.resolve(writer.end());
+      } catch {
+        /* swallow */
+      }
+    },
+    toBytes() {
+      return null;
+    },
+  };
+}
+
+async function createFileHandleSink(handle: {
+  createWritable(): Promise<unknown>;
+}): Promise<OutputSink> {
+  const writable = (await handle.createWritable()) as {
+    write: (chunk: Uint8Array) => Promise<void>;
+    close: () => Promise<void>;
+    abort?: (reason?: unknown) => Promise<void>;
+  };
+  return {
+    async write(chunk) {
+      await writable.write(chunk);
+    },
+    async finalize() {
+      await writable.close();
+    },
+    async abort(reason) {
+      if (writable.abort) await writable.abort(reason);
+      else await writable.close();
+    },
+    toBytes() {
+      return null;
+    },
+  };
+}

packages/shade-transfer/src/receiver/server-handler.ts

@@ -0,0 +1,162 @@
+import type { Hono, Context } from 'hono';
+import type { TransferEngine } from '../engine.js';
+import { TransferProtocolError } from '../errors.js';
+
+/**
+ * Auth contract for incoming chunk POSTs / control GETs. Verifies the
+ * signature attached by the client's `TransferAuthenticator` and returns
+ * the resolved sender address.
+ */
+export interface TransferRouteAuthenticator {
+  verifyChunk(args: {
+    request: Request;
+    streamId: string;
+    laneId: number;
+    seq: bigint;
+    bodyHash: Uint8Array;
+  }): Promise<{ senderAddress: string }>;
+
+  verifyControl(args: {
+    request: Request;
+    streamId: string;
+    method: string;
+    path: string;
+  }): Promise<{ senderAddress: string }>;
+}
+
+export interface TransferRouteOptions {
+  /** Maximum chunk body size in bytes. Default 16 MiB. */
+  maxChunkBytes?: number;
+  /** Server-side authenticator. Defaults to a permissive one for trusted/local nets. */
+  authenticator?: TransferRouteAuthenticator;
+}
+
+/**
+ * Permissive authenticator: extracts sender address from the
+ * `X-Shade-Sender-Address` header without verification. Suitable ONLY for
+ * trusted/local network testing; the SDK's M-Stream-5 integration replaces
+ * this with an Ed25519-verifying implementation.
+ */
+export const PermissiveAuthenticator: TransferRouteAuthenticator = {
+  async verifyChunk({ request }) {
+    const senderAddress = request.headers.get('X-Shade-Sender-Address');
+    if (senderAddress === null || senderAddress === '') {
+      throw new TransferProtocolError('Missing X-Shade-Sender-Address header');
+    }
+    return { senderAddress };
+  },
+  async verifyControl({ request }) {
+    const senderAddress = request.headers.get('X-Shade-Sender-Address');
+    if (senderAddress === null || senderAddress === '') {
+      throw new TransferProtocolError('Missing X-Shade-Sender-Address header');
+    }
+    return { senderAddress };
+  },
+};
+
+const DEFAULT_MAX_CHUNK_BYTES = 16 * 1024 * 1024 + 1024;
+
+/**
+ * Mount the transfer-receive routes on a Hono router. Returns the same
+ * Hono instance for fluent composition. The consumer mounts under any
+ * base path (e.g. `app.route('/shade', createTransferRoutes(engine))`).
+ *
+ * Hono is a peer-dep so non-server consumers can omit it.
+ */
+export async function createTransferRoutes(
+  engine: TransferEngine,
+  options: TransferRouteOptions = {},
+): Promise<Hono> {
+  const { Hono: HonoCtor } = (await import('hono')) as { Hono: new () => Hono };
+  const app = new HonoCtor();
+  const auth = options.authenticator ?? PermissiveAuthenticator;
+  const maxBytes = options.maxChunkBytes ?? DEFAULT_MAX_CHUNK_BYTES;
+
+  app.get('/v1/transfer/health', (c) => c.json({ ok: true }));
+
+  app.post('/v1/transfer/:streamId/chunk', async (c) => {
+    const streamId = c.req.param('streamId');
+    const laneIdRaw = c.req.header('X-Shade-Lane-Id');
+    const seqRaw = c.req.header('X-Shade-Seq');
+    if (laneIdRaw === undefined || seqRaw === undefined) {
+      return c.json({ error: 'missing X-Shade-Lane-Id or X-Shade-Seq' }, 400);
+    }
+    const laneId = Number(laneIdRaw);
+    const seq = BigInt(seqRaw);
+    if (!Number.isInteger(laneId) || laneId < 0) {
+      return c.json({ error: 'invalid lane id' }, 400);
+    }
+
+    const contentLength = c.req.header('content-length');
+    if (contentLength !== undefined && Number(contentLength) > maxBytes) {
+      return c.json({ error: `chunk exceeds maxChunkBytes (${maxBytes})` }, 413);
+    }
+    const ab = await c.req.arrayBuffer();
+    if (ab.byteLength > maxBytes) {
+      return c.json({ error: `chunk exceeds maxChunkBytes (${maxBytes})` }, 413);
+    }
+    const body = new Uint8Array(ab);
+    const bodyHash = new Uint8Array(
+      await globalThis.crypto.subtle.digest('SHA-256', ab),
+    );
+
+    let senderAddress: string;
+    try {
+      const result = await auth.verifyChunk({
+        request: c.req.raw,
+        streamId,
+        laneId,
+        seq,
+        bodyHash,
+      });
+      senderAddress = result.senderAddress;
+    } catch (err) {
+      return errorResponse(c, err);
+    }
+
+    try {
+      const ack = await engine.receiveChunk(senderAddress, streamId, laneId, seq, body);
+      return c.json(ack);
+    } catch (err) {
+      return errorResponse(c, err);
+    }
+  });
+
+  app.get('/v1/transfer/:streamId/state', async (c) => {
+    const streamId = c.req.param('streamId');
+    let senderAddress: string;
+    try {
+      const result = await auth.verifyControl({
+        request: c.req.raw,
+        streamId,
+        method: 'GET',
+        path: c.req.path,
+      });
+      senderAddress = result.senderAddress;
+    } catch (err) {
+      return errorResponse(c, err);
+    }
+
+    const state = await engine.getResumeState(senderAddress, streamId);
+    if (state === null) return c.json({ error: 'no state' }, 404);
+    return c.json(state);
+  });
+
+  return app;
+}
+
+function errorResponse(c: Context, err: unknown): Response {
+  const message = err instanceof Error ? err.message : String(err);
+  const code =
+    err instanceof Error && (err as unknown as { code?: unknown }).code !== undefined
+      ? String((err as unknown as { code: unknown }).code)
+      : 'UNKNOWN';
+  let status = 500;
+  if (code === 'SHADE_TRANSFER_PROTOCOL') status = 400;
+  if (code === 'SHADE_VALIDATION') status = 400;
+  if (code === 'SHADE_UNAUTHORIZED') status = 401;
+  if (code === 'SHADE_INVALID_SIGNATURE') status = 401;
+  if (code === 'SHADE_STREAM_REPLAY') status = 409;
+  if (code === 'SHADE_STREAM_OUT_OF_ORDER') status = 409;
+  return c.json({ error: message, code }, status as 400 | 401 | 409 | 500);
+}