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/schemas/errors.ts

@@ -0,0 +1,228 @@
+import { z } from 'zod';
+import { ShadeError } from '@shade/core';
+
+export const FileErrorCodeSchema = z.enum([
+  'NOT_FOUND',
+  'PERMISSION_DENIED',
+  'CONFLICT',
+  'QUOTA_EXCEEDED',
+  'RATE_LIMIT',
+  'PATH_VALIDATION',
+  'FINGERPRINT_REQUIRED',
+  'OPERATION_TIMEOUT',
+  'IDEMPOTENCY_CONFLICT',
+  'CANCELLED',
+  'INTERNAL',
+  'NOT_IMPLEMENTED',
+  'CUSTOM_OP_REJECTED',
+  'INVALID_SIGNATURE',
+  'INVALID_ARGS',
+]);
+export type FileErrorCode = z.infer<typeof FileErrorCodeSchema>;
+
+export const FileErrorPayloadSchema = z.object({
+  code: FileErrorCodeSchema,
+  message: z.string().max(2048),
+  /** Suggested retry delay in ms; only set for retriable errors (rate limit, transient). */
+  retryAfterMs: z.number().int().nonnegative().optional(),
+  /** Path or arg field the error refers to. */
+  field: z.string().max(128).optional(),
+  /** Optional cause string (sanitized — no stack traces leak from server). */
+  cause: z.string().max(2048).optional(),
+});
+export type FileErrorPayload = z.infer<typeof FileErrorPayloadSchema>;
+
+// ─── Class hierarchy ─────────────────────────────────────────
+
+/**
+ * Base class for all `@shade/files` errors. Extends `ShadeError` so the
+ * existing `errorToHttpStatus()` mapping in `@shade/core` continues to apply.
+ */
+export class FileError extends ShadeError {
+  readonly payload: FileErrorPayload;
+
+  constructor(payload: FileErrorPayload) {
+    super(`SHADE_FS_${payload.code}`, payload.message);
+    this.name = 'FileError';
+    this.payload = payload;
+  }
+
+  override toJSON(): { name: string; code: string; message: string; payload: FileErrorPayload } {
+    return {
+      name: this.name,
+      code: this.code,
+      message: this.message,
+      payload: this.payload,
+    };
+  }
+}
+
+export class NotFoundError extends FileError {
+  constructor(message = 'Not found', field?: string) {
+    super({ code: 'NOT_FOUND', message, ...(field !== undefined ? { field } : {}) });
+    this.name = 'NotFoundError';
+  }
+}
+
+export class PermissionDeniedError extends FileError {
+  constructor(message = 'Permission denied') {
+    super({ code: 'PERMISSION_DENIED', message });
+    this.name = 'PermissionDeniedError';
+  }
+}
+
+export class ConflictError extends FileError {
+  constructor(message: string) {
+    super({ code: 'CONFLICT', message });
+    this.name = 'ConflictError';
+  }
+}
+
+export class QuotaExceededError extends FileError {
+  constructor(message = 'Quota exceeded', retryAfterMs?: number) {
+    super({
+      code: 'QUOTA_EXCEEDED',
+      message,
+      ...(retryAfterMs !== undefined ? { retryAfterMs } : {}),
+    });
+    this.name = 'QuotaExceededError';
+  }
+}
+
+export class FsRateLimitError extends FileError {
+  constructor(message = 'Rate limit exceeded', retryAfterMs?: number) {
+    super({
+      code: 'RATE_LIMIT',
+      message,
+      ...(retryAfterMs !== undefined ? { retryAfterMs } : {}),
+    });
+    this.name = 'FsRateLimitError';
+  }
+}
+
+export class PathValidationError extends FileError {
+  constructor(message: string, field = 'path') {
+    super({ code: 'PATH_VALIDATION', message, field });
+    this.name = 'PathValidationError';
+  }
+}
+
+export class FingerprintRequiredError extends FileError {
+  constructor(message = 'Peer fingerprint must be verified before this operation') {
+    super({ code: 'FINGERPRINT_REQUIRED', message });
+    this.name = 'FingerprintRequiredError';
+  }
+}
+
+export class OperationTimeoutError extends FileError {
+  constructor(message = 'Operation timed out') {
+    super({ code: 'OPERATION_TIMEOUT', message });
+    this.name = 'OperationTimeoutError';
+  }
+}
+
+export class IdempotencyConflictError extends FileError {
+  constructor(
+    message = 'Idempotency key reused with different arguments',
+  ) {
+    super({ code: 'IDEMPOTENCY_CONFLICT', message });
+    this.name = 'IdempotencyConflictError';
+  }
+}
+
+export class CancelledError extends FileError {
+  constructor(message = 'Cancelled') {
+    super({ code: 'CANCELLED', message });
+    this.name = 'CancelledError';
+  }
+}
+
+export class InternalFileError extends FileError {
+  constructor(message = 'Internal server error', cause?: string) {
+    super({
+      code: 'INTERNAL',
+      message,
+      ...(cause !== undefined ? { cause } : {}),
+    });
+    this.name = 'InternalFileError';
+  }
+}
+
+export class NotImplementedError extends FileError {
+  constructor(op: string) {
+    super({ code: 'NOT_IMPLEMENTED', message: `Operation not implemented: ${op}` });
+    this.name = 'NotImplementedError';
+  }
+}
+
+export class CustomOpRejectedError extends FileError {
+  constructor(message: string) {
+    super({ code: 'CUSTOM_OP_REJECTED', message });
+    this.name = 'CustomOpRejectedError';
+  }
+}
+
+export class InvalidSignatureError extends FileError {
+  constructor(message = 'RPC envelope signature verification failed') {
+    super({ code: 'INVALID_SIGNATURE', message });
+    this.name = 'InvalidSignatureError';
+  }
+}
+
+export class InvalidArgsError extends FileError {
+  constructor(message: string, field?: string) {
+    super({ code: 'INVALID_ARGS', message, ...(field !== undefined ? { field } : {}) });
+    this.name = 'InvalidArgsError';
+  }
+}
+
+/**
+ * Reconstruct the right `FileError` subclass from a wire payload. Used by
+ * the client to surface typed errors from server responses.
+ */
+export function fileErrorFromPayload(payload: FileErrorPayload): FileError {
+  switch (payload.code) {
+    case 'NOT_FOUND':
+      return new NotFoundError(payload.message, payload.field);
+    case 'PERMISSION_DENIED':
+      return new PermissionDeniedError(payload.message);
+    case 'CONFLICT':
+      return new ConflictError(payload.message);
+    case 'QUOTA_EXCEEDED':
+      return new QuotaExceededError(payload.message, payload.retryAfterMs);
+    case 'RATE_LIMIT':
+      return new FsRateLimitError(payload.message, payload.retryAfterMs);
+    case 'PATH_VALIDATION':
+      return new PathValidationError(payload.message, payload.field);
+    case 'FINGERPRINT_REQUIRED':
+      return new FingerprintRequiredError(payload.message);
+    case 'OPERATION_TIMEOUT':
+      return new OperationTimeoutError(payload.message);
+    case 'IDEMPOTENCY_CONFLICT':
+      return new IdempotencyConflictError(payload.message);
+    case 'CANCELLED':
+      return new CancelledError(payload.message);
+    case 'INTERNAL':
+      return new InternalFileError(payload.message, payload.cause);
+    case 'NOT_IMPLEMENTED':
+      return new NotImplementedError(payload.message);
+    case 'CUSTOM_OP_REJECTED':
+      return new CustomOpRejectedError(payload.message);
+    case 'INVALID_SIGNATURE':
+      return new InvalidSignatureError(payload.message);
+    case 'INVALID_ARGS':
+      return new InvalidArgsError(payload.message, payload.field);
+  }
+}
+
+/** Convert any thrown value into a `FileErrorPayload` for wire serialization. */
+export function payloadFromError(err: unknown): FileErrorPayload {
+  if (err instanceof FileError) return err.payload;
+  if (err instanceof Error) {
+    return {
+      code: 'INTERNAL',
+      message: err.message.slice(0, 2048),
+    };
+  }
+  return { code: 'INTERNAL', message: 'unknown error' };
+}