fix: security hardening + performance refactoring (code review batch 1)

- IDOR fix: deliberation vote now verifies juryMemberId === ctx.user.id
- Rate limiting: tRPC middleware (100/min), AI endpoints (5/hr), auth IP-based (10/15min)
- 6 compound indexes added to Prisma schema
- N+1 eliminated in processRoundClose (batch updateMany/createMany)
- N+1 eliminated in batchCheckRequirementsAndTransition (3 batch queries)
- Service extraction: juror-reassignment.ts (578 lines)
- Dead code removed: award.ts, cohort.ts, decision.ts (680 lines)
- 35 bare catch blocks replaced across 16 files
- Fire-and-forget async calls fixed
- Notification false positive bug fixed

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

src/server/routers/applicant.ts

@@ -1008,7 +1008,8 @@ export const applicantRouter = router({
               errorMsg: error instanceof Error ? error.message : 'Unknown error',
             },
           })
-        } catch {
+        } catch (err) {
+          console.error('Failed to log failed team invitation notification:', err)
           // Never fail on notification logging
         }
 
@@ -1043,7 +1044,8 @@ export const applicantRouter = router({
             status: 'SENT',
           },
         })
-      } catch {
+      } catch (err) {
+        console.error('Failed to log sent team invitation notification:', err)
         // Never fail on notification logging
       }
 
@@ -1061,7 +1063,8 @@ export const applicantRouter = router({
             projectName: project.title,
           },
         })
-      } catch {
+      } catch (err) {
+        console.error('Failed to create in-app team invitation notification:', err)
         // Never fail invitation flow on in-app notification issues
       }