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-widgets/src/useShadeUpload.ts

@@ -0,0 +1,90 @@
+import { useCallback, useEffect, useRef, useState } from 'react';
+import type { TransferHandle, TransferOptions, TransferProgress } from '@shade/sdk';
+import { useShadeRuntime } from './ShadeRuntimeProvider.js';
+
+export interface UploadEntry {
+  handle: TransferHandle;
+  progress: TransferProgress | null;
+  error: unknown;
+  done: boolean;
+}
+
+export interface UseShadeUploadResult {
+  /** Start a new upload. Resolves once the handle is available. */
+  upload: (opts: TransferOptions) => Promise<TransferHandle>;
+  /** Currently-tracked uploads (most recent first). */
+  uploads: UploadEntry[];
+  /** Drop a finished/failed entry from the list. */
+  dismiss: (streamId: string) => void;
+}
+
+/**
+ * Headless hook for upload tracking. Subscribes to progress events on each
+ * started transfer and surfaces them as React state. Drop a custom UI on
+ * top, or use the bundled `<ShadeUploader />` component.
+ */
+export function useShadeUpload(): UseShadeUploadResult {
+  const shade = useShadeRuntime();
+  const [uploads, setUploads] = useState<UploadEntry[]>([]);
+  const mountedRef = useRef(true);
+
+  useEffect(() => {
+    mountedRef.current = true;
+    return () => {
+      mountedRef.current = false;
+    };
+  }, []);
+
+  const upload = useCallback(
+    async (opts: TransferOptions) => {
+      const handle = await shade.upload(opts);
+      const entry: UploadEntry = { handle, progress: null, error: null, done: false };
+      setUploads((prev) => [entry, ...prev]);
+
+      void (async () => {
+        try {
+          for await (const ev of handle.events) {
+            if (!mountedRef.current) return;
+            if (ev.type === 'progress') {
+              setUploads((prev) =>
+                prev.map((u) =>
+                  u.handle.streamId === handle.streamId ? { ...u, progress: ev.progress } : u,
+                ),
+              );
+            } else if (ev.type === 'complete') {
+              setUploads((prev) =>
+                prev.map((u) =>
+                  u.handle.streamId === handle.streamId ? { ...u, done: true } : u,
+                ),
+              );
+            } else if (ev.type === 'error') {
+              setUploads((prev) =>
+                prev.map((u) =>
+                  u.handle.streamId === handle.streamId
+                    ? { ...u, error: ev.error, done: true }
+                    : u,
+                ),
+              );
+            }
+          }
+        } catch (err) {
+          if (!mountedRef.current) return;
+          setUploads((prev) =>
+            prev.map((u) =>
+              u.handle.streamId === handle.streamId ? { ...u, error: err, done: true } : u,
+            ),
+          );
+        }
+      })();
+
+      return handle;
+    },
+    [shade],
+  );
+
+  const dismiss = useCallback((streamId: string) => {
+    setUploads((prev) => prev.filter((u) => u.handle.streamId !== streamId));
+  }, []);
+
+  return { upload, uploads, dismiss };
+}