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/tests/unit/path-policy.test.ts

@@ -0,0 +1,128 @@
+import { describe, test, expect } from 'bun:test';
+import * as fc from 'fast-check';
+import { validatePath } from '../../src/index.js';
+
+describe('validatePath — happy path', () => {
+  test('accepts simple absolute paths', () => {
+    expect(validatePath('/foo')).toEqual({ ok: true, normalized: '/foo' });
+    expect(validatePath('/foo/bar/baz.txt')).toEqual({
+      ok: true,
+      normalized: '/foo/bar/baz.txt',
+    });
+    expect(validatePath('/')).toEqual({ ok: true, normalized: '/' });
+  });
+
+  test('normalizes redundant slashes and dots', () => {
+    expect(validatePath('//foo//bar/./baz/').normalized).toBe('/foo/bar/baz');
+    expect(validatePath('/./foo').normalized).toBe('/foo');
+  });
+
+  test('UTF-8 paths are accepted', () => {
+    expect(validatePath('/Документы/файл.txt').normalized).toBe('/Документы/файл.txt');
+    expect(validatePath('/絵文字 😀/foo').normalized).toBe('/絵文字 😀/foo');
+  });
+});
+
+describe('validatePath — security', () => {
+  test('rejects raw `..` segments', () => {
+    expect(validatePath('/../etc/passwd').ok).toBe(false);
+    expect(validatePath('/foo/../etc').ok).toBe(false);
+    expect(validatePath('/..').ok).toBe(false);
+  });
+
+  test('rejects percent-encoded `..`', () => {
+    expect(validatePath('/%2e%2e/etc').ok).toBe(false);
+    expect(validatePath('/foo/%2E%2E/etc').ok).toBe(false);
+  });
+
+  test('rejects forbidden control bytes', () => {
+    expect(validatePath('/foo\x00bar').ok).toBe(false);
+    expect(validatePath('/foo\r\nbar').ok).toBe(false);
+    expect(validatePath('/foo\x7f').ok).toBe(false);
+    expect(validatePath('/foo\x01').ok).toBe(false);
+  });
+
+  test('rejects backslashes (Windows-style)', () => {
+    expect(validatePath('/foo\\bar').ok).toBe(false);
+  });
+
+  test('rejects relative paths', () => {
+    expect(validatePath('foo').ok).toBe(false);
+    expect(validatePath('./foo').ok).toBe(false);
+    expect(validatePath('').ok).toBe(false);
+  });
+
+  test('rejects over-length paths', () => {
+    expect(validatePath('/' + 'a'.repeat(4096)).ok).toBe(false);
+    expect(validatePath('/foobar', { maxLength: 5 }).ok).toBe(false);
+    expect(validatePath('/abc', { maxLength: 5 }).ok).toBe(true);
+  });
+});
+
+describe('validatePath — rootScope', () => {
+  test('accepts paths inside scope', () => {
+    expect(
+      validatePath('/srv/data/foo', { rootScope: '/srv/data' }).ok,
+    ).toBe(true);
+    expect(validatePath('/srv/data', { rootScope: '/srv/data' }).ok).toBe(true);
+  });
+
+  test('rejects paths outside scope', () => {
+    expect(validatePath('/etc/passwd', { rootScope: '/srv/data' }).ok).toBe(false);
+    expect(validatePath('/srv/dataX', { rootScope: '/srv/data' }).ok).toBe(false);
+    // Boundary check: /srv/database is NOT inside /srv/data
+    expect(validatePath('/srv/database/x', { rootScope: '/srv/data' }).ok).toBe(false);
+  });
+});
+
+describe('validatePath — extra hook', () => {
+  test('extra reject takes precedence', () => {
+    const result = validatePath('/secret/foo', {
+      extra: (p) => (p.includes('secret') ? 'reject' : 'allow'),
+    });
+    expect(result.ok).toBe(false);
+  });
+
+  test('extra allow is the default', () => {
+    expect(
+      validatePath('/foo', {
+        extra: () => 'allow',
+      }).ok,
+    ).toBe(true);
+  });
+});
+
+describe('validatePath — property-based', () => {
+  test('any string with a forbidden control byte is rejected', () => {
+    fc.assert(
+      fc.property(
+        fc.string({ minLength: 1, maxLength: 100 }),
+        fc.constantFrom('\x00', '\x07', '\x0a', '\x0d', '\x7f', '\\'),
+        (prefix, bad) => {
+          const p = `/${prefix}${bad}`;
+          expect(validatePath(p).ok).toBe(false);
+        },
+      ),
+      { numRuns: 200 },
+    );
+  });
+
+  test('any path inside rootScope normalizes within rootScope', () => {
+    fc.assert(
+      fc.property(
+        fc.array(fc.string({ minLength: 1, maxLength: 20 }).filter(
+          (s) => /^[A-Za-z0-9_-]+$/.test(s),
+        ), { minLength: 1, maxLength: 5 }),
+        (segments) => {
+          const root = '/srv';
+          const path = `${root}/${segments.join('/')}`;
+          const r = validatePath(path, { rootScope: root });
+          if (r.ok) {
+            expect(r.normalized.startsWith(root)).toBe(true);
+          }
+        },
+      ),
+      { numRuns: 200 },
+    );
+  });
+});