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/src/index.ts

@@ -0,0 +1,198 @@
+// Schemas — Zod runtime + compile-time types
+export * from './schemas/index.js';
+
+// Protocol primitives — kinds, correlation, canonical bytes, envelope codec
+export {
+  SHADE_FILES_VERSION,
+  KIND_PREFIX,
+  SUPPORTED_KINDS,
+  isSupportedKind,
+} from './protocol/version.js';
+export type { SupportedKind } from './protocol/version.js';
+export {
+  KIND_LIST_V1,
+  KIND_STAT_V1,
+  KIND_MKDIR_V1,
+  KIND_DELETE_V1,
+  KIND_MOVE_V1,
+  KIND_READ_V1,
+  KIND_WRITE_V1,
+  KIND_GET_THUMBNAIL_V1,
+  KIND_CUSTOM_V1,
+  KIND_ERROR_V1,
+  KIND_CANCEL_V1,
+  responseKindOf,
+  opOfKind,
+  MUTATION_OPS,
+} from './protocol/kinds.js';
+export type { StandardOp } from './protocol/kinds.js';
+export {
+  generateRequestId,
+  generateIdempotencyKey,
+  base64UrlEncode,
+  base64UrlDecode,
+} from './protocol/correlate.js';
+export {
+  canonicalRpcBytes,
+  canonicalJsonStringify,
+  hashArgs,
+  bytesToHex,
+  bytesToBase64,
+  base64ToBytes,
+} from './protocol/canonical.js';
+export {
+  encodeEnvelope,
+  looksLikeFileEnvelope,
+  tryParseEnvelope,
+  classify,
+} from './protocol/envelope-codec.js';
+export type { ClassifiedEnvelope } from './protocol/envelope-codec.js';
+
+// RPC channel — wires Shade.send/onMessage to the file-RPC routing layer
+export { ShadeFileRpcChannel } from './rpc/channel.js';
+export type { RpcChannelHooks } from './rpc/channel.js';
+export { PendingRpcRegistry } from './rpc/pending.js';
+export type { RegisterOptions } from './rpc/pending.js';
+
+// Server side
+export { createFileHandler, INTERNAL_SYMBOL } from './server/handler.js';
+export type {
+  FileHandler,
+  FileHandlerConfig,
+  FileHandlerOps,
+} from './server/handler.js';
+export type { OpContext, OpKind } from './server/handler-context.js';
+export { validatePath } from './server/path-policy.js';
+export type { PathPolicy, PathValidationResult } from './server/path-policy.js';
+export { IdempotencyCache } from './server/idempotency-cache.js';
+export type { IdempotencyCacheOptions } from './server/idempotency-cache.js';
+export { RateLimiter } from './server/rate-limiter.js';
+export type { RateLimitConfig } from './server/rate-limiter.js';
+export { createCursorBuilder } from './server/cursor.js';
+export type { CursorBuilder } from './server/cursor.js';
+export {
+  createServerStreamsBridge,
+  META_KEY_READ_STREAM_ID,
+  META_KEY_WRITE_ID,
+} from './server/streams-bridge.js';
+export type {
+  ServerStreamsBridge,
+  StreamsBridgeShade,
+  CreateServerStreamsBridgeOptions,
+  ParkedWrite,
+  AwaitWriteOptions,
+} from './server/streams-bridge.js';
+export type {
+  UserReadResult,
+  UserReadResultInline,
+  UserReadResultStreams,
+  UserWriteArgs,
+  UserWriteContent,
+  UserWriteContentInline,
+  UserWriteContentStreams,
+  UserThumbnailResult,
+} from './server/io-types.js';
+export {
+  assertThumbnailFormat,
+  isThumbnailFormat,
+} from './server/thumbnail.js';
+export type { ThumbnailFormat } from './server/thumbnail.js';
+
+// Client side
+export { createFileClient } from './client/client.js';
+export type {
+  FileClient,
+  BaseOpts,
+  CreateFileClientOptions,
+  ReadOpts,
+  WriteOpts,
+  ReadOutput,
+  ReadInlineOutput,
+  ReadStreamsOutput,
+  ThumbnailResult,
+} from './client/client.js';
+export {
+  createClientStreamsBridge,
+} from './client/streams-bridge.js';
+export type {
+  ClientStreamsBridge,
+  CreateClientStreamsBridgeOptions,
+  AwaitReadOptions,
+  ParkedRead,
+} from './client/streams-bridge.js';
+export {
+  decideInline,
+  INLINE_THRESHOLD,
+} from './client/inline-threshold.js';
+export type {
+  InlineDecision,
+  WriteSource,
+} from './client/inline-threshold.js';
+
+// Directory ops — walk + bulk transfers
+export { walk } from './client/walk.js';
+export type { WalkOpts, WalkItem } from './client/walk.js';
+export { uploadDirectory } from './client/upload-directory.js';
+export type { UploadDirectoryOptions } from './client/upload-directory.js';
+export { downloadDirectory } from './client/download-directory.js';
+export type { DownloadDirectoryOptions } from './client/download-directory.js';
+export { runWithConcurrency } from './client/concurrency.js';
+export type { ConcurrentMapOptions } from './client/concurrency.js';
+export {
+  DEFAULT_BULK_CONCURRENCY,
+  MAX_BULK_CONCURRENCY,
+} from './client/directory-types.js';
+export type {
+  BulkOpts,
+  BulkTransferEvent,
+  BulkTransferHandle,
+  BulkTransferResult,
+  DirectoryHandleLike,
+  FileHandleLike,
+  FileLike,
+  WritableStreamLike,
+} from './client/directory-types.js';
+export { createMemoryDirectory } from './client/memory-directory.js';
+
+// Custom-op registry typing (declaration-merged by consumers)
+export type {
+  CustomOpDef,
+  CustomOpsMap,
+  CustomOpRegistration,
+  CustomOpRegistrations,
+} from './server/custom-ops.js';
+
+// Production hooks: metrics
+export {
+  METRIC_BYTES_IN,
+  METRIC_BYTES_OUT,
+  METRIC_FINGERPRINT_REJECT_TOTAL,
+  METRIC_IDEMPOTENCY_CONFLICT_TOTAL,
+  METRIC_IDEMPOTENCY_HIT_TOTAL,
+  METRIC_OP_DURATION_MS,
+  METRIC_OP_TOTAL,
+  METRIC_RATE_LIMIT_REJECT_TOTAL,
+  METRIC_SIGNATURE_REJECT_TOTAL,
+  NOOP_METRIC_SINK,
+} from './server/metrics.js';
+export type { MetricSink, MetricTags } from './server/metrics.js';
+
+export { MAX_SIGNATURE_AGE_MS } from './server/handler.js';
+
+// High-level SDK integration entrypoint
+export { createFilesNamespace } from './integration/files-namespace.js';
+export type { FilesNamespace } from './integration/files-namespace.js';
+
+// Integration helpers — wire handler + pending registry onto a channel
+export { attachFileHandler } from './integration/wire-server.js';
+export { attachClientRouting } from './integration/wire-client.js';
+
+// Path utilities
+export {
+  posixNormalize,
+  posixJoin,
+  posixDirname,
+  posixBasename,
+  decodePercentEscapes,
+  isPathInside,
+} from './utils/path.js';