release(v4.9.0): relay-side encrypted blob primitive + SDK Profile namespace

Ships the Prism FR (encrypted-profile-storage-v4.9.md) as a generic
relay-side encrypted blob primitive: deterministically-located,
AEAD-sealed blobs keyed by a 32-byte slotId derived client-side via
HKDF from the user's master key. Unlocks credential-only bootstrap
of new devices into existing E2EE state — no QR, no physical access.

Server: BlobStore interface + Memory/Sqlite/Postgres impls,
createBlobRoutes for GET/PUT/DELETE /v1/blob/:slotId with TOFU pubkey
auth and If-Match CAS (409/412 semantics). Mounted on the same Hono
app as the inbox; SHADE_BLOB_PG_URL / SHADE_BLOB_DB_PATH /
SHADE_DISABLE_BLOB env-var plumbing in standalone.

SDK: createProfileNamespace high-level wrapper (HKDF derivation,
random-nonce AEAD seal, slotId-bound AAD) + low-level BlobClient.
Cross-platform test vectors in test-vectors/blob-storage.json.

New errors: ConflictError (409), PreconditionFailedError (412).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

packages/shade-storage-encrypted/tests/blob-vectors.test.ts

@@ -0,0 +1,50 @@
+import { describe, test, expect } from 'bun:test';
+import { readFileSync } from 'fs';
+import { join } from 'path';
+import {
+  deriveBlobSlotId,
+  deriveBlobKey,
+  deriveBlobSigningSeed,
+} from '../src/crypto/kdf.js';
+import { ed25519PublicKeyFromSeed } from '@shade/crypto-web';
+
+function fromHex(s: string): Uint8Array {
+  const out = new Uint8Array(s.length / 2);
+  for (let i = 0; i < out.length; i++) {
+    out[i] = parseInt(s.substr(i * 2, 2), 16);
+  }
+  return out;
+}
+
+function toHex(b: Uint8Array): string {
+  let s = '';
+  for (const x of b) s += x.toString(16).padStart(2, '0');
+  return s;
+}
+
+describe('V4.9 blob-storage KDF vectors', () => {
+  // Resolve relative to this file, not to cwd, so the test passes
+  // regardless of which directory `bun test` is invoked from.
+  const vectorPath = join(import.meta.dir, '..', '..', '..', 'test-vectors', 'blob-storage.json');
+  const vectors = JSON.parse(readFileSync(vectorPath, 'utf-8')) as {
+    kdf: Array<{
+      masterKey: string;
+      app: string;
+      slotId: string;
+      blobKey: string;
+      signingSeed: string;
+      ownerPubkey: string;
+    }>;
+  };
+
+  for (const v of vectors.kdf) {
+    test(`(master=${v.masterKey.slice(0, 8)}…, app=${v.app})`, () => {
+      const km = fromHex(v.masterKey);
+      expect(toHex(deriveBlobSlotId(km, v.app))).toBe(v.slotId);
+      expect(toHex(deriveBlobKey(km, v.app))).toBe(v.blobKey);
+      const seed = deriveBlobSigningSeed(km, v.app);
+      expect(toHex(seed)).toBe(v.signingSeed);
+      expect(toHex(ed25519PublicKeyFromSeed(seed))).toBe(v.ownerPubkey);
+    });
+  }
+});