Fix 3 defects in insight engine v3 intraday analyzers

1. Blacklist query error handling: log warning if insight_engine_blacklist
   table is missing instead of silently ignoring (pattern-spotter.ts)

2. Fix double-Z timestamp bug in sequential-change-analyzer: appending "Z"
   to localTimestamp that already ends with "Z" (from glucose display_time)
   produced "...ZZ" → NaN, silently breaking dawn phenomenon detection for
   CGM users

3. Standardize Z-suffix handling across all 4 intraday analyzers: use
   conditional append (ts.endsWith("Z") ? ts : ts + "Z") so hour extraction
   works correctly in both UTC production runtime and non-UTC dev environments

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

Author: schwaaamp

supabase/functions/_shared/excursion-cluster-analyzer.ts

@@ -82,7 +82,7 @@ function findExcursionStartHours(
       runLength++;
     } else {
       if (runLength >= minConsecutive) {
-        const hour = new Date(sortedReadings[runStart].localTimestamp).getUTCHours();
+        const hour = new Date(sortedReadings[runStart].localTimestamp.endsWith("Z") ? sortedReadings[runStart].localTimestamp : sortedReadings[runStart].localTimestamp + "Z").getUTCHours();
         startHours.push(hour);
       }
       runLength = 0;
@@ -91,7 +91,7 @@ function findExcursionStartHours(
 
   // Handle trailing run
   if (runLength >= minConsecutive) {
-    const hour = new Date(sortedReadings[runStart].localTimestamp).getUTCHours();
+    const hour = new Date(sortedReadings[runStart].localTimestamp.endsWith("Z") ? sortedReadings[runStart].localTimestamp : sortedReadings[runStart].localTimestamp + "Z").getUTCHours();
     startHours.push(hour);
   }
 

supabase/functions/_shared/sequential-change-analyzer.ts

@@ -76,7 +76,7 @@ export function _computeDailyProfile(
 
   for (const r of readings) {
     const date = r.localTimestamp.substring(0, 10);
-    const hour = new Date(`${r.localTimestamp}Z`).getUTCHours();
+    const hour = new Date(r.localTimestamp.endsWith("Z") ? r.localTimestamp : r.localTimestamp + "Z").getUTCHours();
     const bucket = Math.floor(hour / 3);
 
     if (!dayBuckets.has(date)) {
@@ -147,7 +147,7 @@ export function analyzeSequentialChanges(
 
   for (const r of config.readings) {
     const date = r.localTimestamp.substring(0, 10);
-    const hour = new Date(`${r.localTimestamp}Z`).getUTCHours();
+    const hour = new Date(r.localTimestamp.endsWith("Z") ? r.localTimestamp : r.localTimestamp + "Z").getUTCHours();
     const bucket = Math.floor(hour / 3);
 
     if (!dayBuckets.has(date)) {

supabase/functions/_shared/temporal-distribution-analyzer.ts

@@ -101,7 +101,8 @@ export function analyzeTemporalDistribution(
   let maxTs = -Infinity;
 
   for (const r of readings) {
-    const d = new Date(r.localTimestamp);
+    const tsForParse = r.localTimestamp.endsWith("Z") ? r.localTimestamp : r.localTimestamp + "Z";
+    const d = new Date(tsForParse);
     const hour = d.getUTCHours();
     const bucketIdx = hourToBucket(hour);
     buckets[bucketIdx].push(r.value);

supabase/functions/ai-engine/engines/pattern-spotter.ts

@@ -172,11 +172,15 @@ export async function spotPatterns(
   const localTime = createLocalTimeExtractors(timezone);
 
   // Load blacklist for tautological pair prevention
-  const { data: blacklistRows } = await supabase
+  const { data: blacklistRows, error: blacklistError } = await supabase
     .from('insight_engine_blacklist')
     .select('metric_a, metric_b')
     .eq('is_active', true);
 
+  if (blacklistError) {
+    console.warn(`[PatternSpotter] ⚠ Failed to load blacklist: ${blacklistError.message} — continuing without blacklist`);
+  }
+
   const blacklist = new Set<string>(
     (blacklistRows ?? []).map((r: Record<string, unknown>) => `${r.metric_a}::${r.metric_b}`)
   );