js-rigor: re-entrant temporal diagnostics — pinned-clock checks + explain replay

The errors-skill's two-pass model applied without a journal: the caller
owns the temporal context. Every decision-flipping temporal feature (the
clock behind TTL gates, challenge-proof expiry, value decay) is now
parameterized as options.now, so an explain rerun that replays the
original temporal parameters reproduces the original decision exactly.

Threaded now through: the comparator's operand value paths
(_getCachedDirectValue/_extractValues/isWithinTTL), the challenge proof
lookup, and the multi_hop value collection (isWithinTTL + blur). All four
result caches bypass cached decisions when the clock is pinned (rule-
result cache, the checker's rule/direct caches, and the comparator's
derived operand cache) — interleaved pinned-clock checks are per-time
with no cross-contamination.

The explain serializer records request.temporal.now so the caller knows
exactly what to replay. The happy path stays minimal and fast (no now ->
no parameter, no cache changes); the rerun (explain with the temporal
context) carries the full diagnostics.

Pins: interleaved fresh/expired/expired-again comparator checks, the
explain replay of both decisions + the recorded temporal context, and
challenge-proof expiry replay.

src/utils/OWAFusion.js

@@ -1012,9 +1012,9 @@ export class OWAFusion {
    * @param {number} ttlMs - TTL in milliseconds (default 24 hours)
    * @returns {boolean} Whether the value is within TTL
    */
-  static isWithinTTL(timestamp, ttlMs = 24 * 60 * 60 * 1000) {
+  static isWithinTTL(timestamp, ttlMs = 24 * 60 * 60 * 1000, now = null) {
     if (!timestamp) return false;
-    const age = Date.now() - timestamp;
+    const age = (now !== null && now !== undefined ? now : Date.now()) - timestamp;
     return age <= ttlMs;
   }