fix: tech debt batch 1 — TS errors, vulnerabilities, dead code

- Fixed 12 TypeScript errors across analytics.ts, observer-project-detail.tsx, bulk-upload/page.tsx, settings/profile/page.tsx
- npm audit: 8 vulnerabilities resolved (1 critical, 4 high, 3 moderate)
- Deleted 3 dead files: live-control.ts (618 lines), feature-flags.ts, file-type-categories.ts
- Removed typescript.ignoreBuildErrors: true — TS errors now block builds

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/app/(settings)/settings/profile/page.tsx

@@ -94,10 +94,10 @@ export default function ProfileSettingsPage() {
       setExpertiseTags(user.expertiseTags || [])
       setDigestFrequency(user.digestFrequency || 'none')
       setPreferredWorkload(user.preferredWorkload ?? null)
-      const avail = user.availabilityJson as { startDate?: string; endDate?: string } | null
-      if (avail) {
-        setAvailabilityStart(avail.startDate || '')
-        setAvailabilityEnd(avail.endDate || '')
+      const avail = user.availabilityJson as Array<{ start?: string; end?: string }> | null
+      if (avail && avail.length > 0) {
+        setAvailabilityStart(avail[0].start || '')
+        setAvailabilityEnd(avail[0].end || '')
       }
       setProfileLoaded(true)
     }
@@ -114,10 +114,10 @@ export default function ProfileSettingsPage() {
         expertiseTags,
         digestFrequency: digestFrequency as 'none' | 'daily' | 'weekly',
         preferredWorkload: preferredWorkload ?? undefined,
-        availabilityJson: (availabilityStart || availabilityEnd) ? {
-          startDate: availabilityStart || undefined,
-          endDate: availabilityEnd || undefined,
-        } : undefined,
+        availabilityJson: (availabilityStart || availabilityEnd) ? [{
+          start: availabilityStart || '',
+          end: availabilityEnd || '',
+        }] : undefined,
       })
       toast.success('Profile updated successfully')
       refetch()