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/react/useFileTransfer.ts

@@ -0,0 +1,103 @@
+import { useCallback, useEffect, useRef, useState } from 'react';
+import type { BulkTransferEvent, BulkTransferHandle, BulkTransferResult } from '../client/directory-types.js';
+
+export interface BulkTransferStatus {
+  state: 'idle' | 'running' | 'done' | 'error' | 'aborted';
+  filesDone: number;
+  filesTotal: number;
+  bytesDone: number;
+  bytesTotal: number;
+  error: unknown;
+  result: BulkTransferResult | null;
+  /** Last event emitted by the underlying handle. */
+  lastEvent: BulkTransferEvent | null;
+}
+
+export interface UseFileTransferResult extends BulkTransferStatus {
+  start(handle: BulkTransferHandle): void;
+  abort(reason?: string): Promise<void>;
+}
+
+const INITIAL: BulkTransferStatus = {
+  state: 'idle',
+  filesDone: 0,
+  filesTotal: 0,
+  bytesDone: 0,
+  bytesTotal: 0,
+  error: null,
+  result: null,
+  lastEvent: null,
+};
+
+/**
+ * Generic React-state wrapper around a `BulkTransferHandle`. Apps wire the
+ * handle returned from `uploadDirectory()` / `downloadDirectory()` here to
+ * surface progress in their UI.
+ *
+ * `useFileUpload` and `useFileDownload` are thin presets — they call
+ * `start(...)` with the appropriate handle automatically.
+ */
+export function useFileTransfer(): UseFileTransferResult {
+  const [status, setStatus] = useState<BulkTransferStatus>(INITIAL);
+  const handleRef = useRef<BulkTransferHandle | null>(null);
+
+  const start = useCallback((handle: BulkTransferHandle): void => {
+    handleRef.current = handle;
+    setStatus({ ...INITIAL, state: 'running' });
+    void (async () => {
+      try {
+        for await (const ev of handle.events) {
+          setStatus((prev) => {
+            const next: BulkTransferStatus = { ...prev, lastEvent: ev };
+            if (ev.type === 'plan') {
+              next.filesTotal = ev.totalFiles;
+              next.bytesTotal = ev.totalBytes ?? 0;
+            } else if (ev.type === 'progress') {
+              next.filesDone = ev.filesDone;
+              next.bytesDone = ev.bytesDone;
+              next.bytesTotal = ev.bytesTotal ?? prev.bytesTotal;
+              next.filesTotal = ev.filesTotal;
+            } else if (ev.type === 'complete') {
+              next.state = 'done';
+              next.filesDone = ev.filesDone;
+              next.bytesDone = ev.bytesDone;
+            } else if (ev.type === 'abort') {
+              next.state = 'aborted';
+              next.error = new Error(ev.reason);
+            } else if (ev.type === 'file-error') {
+              next.error = ev.error;
+            }
+            return next;
+          });
+        }
+        const result = await handle.done();
+        setStatus((prev) => ({ ...prev, state: 'done', result }));
+      } catch (err) {
+        setStatus((prev) => ({ ...prev, state: 'error', error: err }));
+      }
+    })();
+  }, []);
+
+  const abort = useCallback(async (reason?: string): Promise<void> => {
+    if (handleRef.current === null) return;
+    await handleRef.current.abort(reason);
+  }, []);
+
+  // Cleanup on unmount: abort any in-flight transfer.
+  useEffect(() => {
+    return () => {
+      if (handleRef.current !== null) {
+        void handleRef.current.abort('unmount').catch(() => undefined);
+      }
+    };
+  }, []);
+
+  return { ...status, start, abort };
+}
+
+/**
+ * Preset: `useFileUpload` — semantically identical to `useFileTransfer`,
+ * named distinctly to mirror the `useFileDownload` pair.
+ */
+export const useFileUpload = useFileTransfer;
+export const useFileDownload = useFileTransfer;