fix(security): resolve all 17 codex findings — auth, grants, crypto, ops

Critical: broker HTTP auth via cli_session bearer token on all /cli/*;
file download requires auth+membership; v2 claim gated; duplicate
claimInviteV2Core removed; grant enforcement tries member then
session pubkey; audit hash uses canonical sorted-keys JSON.

High: rate limit args fixed (burst 10, 60/min) + both buckets swept;
BROKER_ENCRYPTION_KEY fail-fast in prod; migrate uses pg_try + lock_
timeout; hello validates sessionPubkey hex; blocked DMs rejected pre-
queue; watch timers cleaned on disconnect.

Medium: inbound pushes serialized; reconnect jitter + timer guard;
hardcoded URLs through env; v2 claim path configurable.

Low: WSHelloMessage optional protocolVersion+capabilities.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

apps/broker/src/audit.ts

@@ -25,6 +25,29 @@ const lastHash = new Map<string, string>();
 // Core audit logging
 // ---------------------------------------------------------------------------
 
+/**
+ * Deterministic JSON serialization: keys sorted recursively. The store
+ * is JSONB, which does NOT preserve key order, so hashing a naive
+ * JSON.stringify(row.payload) on verify can yield a different string
+ * from insert-time — false tamper reports. Canonical form guarantees
+ * both sides agree.
+ */
+function canonicalJson(value: unknown): string {
+  if (value === null || typeof value !== "object") return JSON.stringify(value);
+  if (Array.isArray(value)) {
+    return "[" + value.map(canonicalJson).join(",") + "]";
+  }
+  const obj = value as Record<string, unknown>;
+  const keys = Object.keys(obj).sort();
+  return (
+    "{" +
+    keys
+      .map((k) => JSON.stringify(k) + ":" + canonicalJson(obj[k]))
+      .join(",") +
+    "}"
+  );
+}
+
 function computeHash(
   prevHash: string,
   meshId: string,
@@ -33,7 +56,7 @@ function computeHash(
   payload: Record<string, unknown>,
   createdAt: Date,
 ): string {
-  const input = `${prevHash}|${meshId}|${eventType}|${actorMemberId}|${JSON.stringify(payload)}|${createdAt.toISOString()}`;
+  const input = `${prevHash}|${meshId}|${eventType}|${actorMemberId}|${canonicalJson(payload)}|${createdAt.toISOString()}`;
   return createHash("sha256").update(input).digest("hex");
 }