refactor: fix all P0/P1/P2 bugs and architecture issues

Bug fixes (from bugs/ directory):

- Fix cross-module DB queries in 9 modules (homework, grades, parent, diagnostic, elective, proctoring, notifications, scheduling, classes) by routing through data-access functions

- Fix shared/lib <-> auth circular dependency via new session.ts module

- Fix divide-by-zero guard in grades data-access

- Fix audit export data truncation (paginated fetch for full datasets)

- Fix missing transactions in homework grading and elective lottery

- Fix missing revalidatePath in course-plans actions

- Fix frontend permission checks using requirePermission instead of requireAuth

- Fix dashboard role routing using session.user.roles

- Fix student auth pattern (migrate getDemoStudentUser to users module)

- Fix ActionState return type handling in components

Code quality fixes:

- Remove 60+ as type assertions (replace with type guards)

- Remove non-null assertions (use optional chaining or explicit checks)

- Convert dynamic imports to static imports (grades, diagnostic)

- Add React.cache() wrapping for read functions

- Parallelize independent queries with Promise.all

- Add explicit return types to 30+ arrow functions

- Replace any with unknown + type guards

- Fix import type for type-only imports

- Add Zod validation schemas for classes and diagnostic modules

- Extract duplicate code (normalizeRoleName, normalizeBcryptHash, logger IP extraction)

- Add console.error to silent catch blocks

- Fix permission naming consistency (exam:proctor_read -> exam:proctor:read)

Architecture doc sync:

- Update 004_architecture_impact_map.md and 005_architecture_data.json

- Update management-modules-audit.md for P0-7 cross-module fix

Moved deleted proctoring event route to deletes/ folder.

src/app/(dashboard)/student/learning/assignments/page.tsx

@@ -5,7 +5,8 @@ import { Badge } from "@/shared/components/ui/badge"
 import { Button } from "@/shared/components/ui/button"
 import { Card, CardContent, CardHeader, CardTitle } from "@/shared/components/ui/card"
 import { formatDate } from "@/shared/lib/utils"
-import { getDemoStudentUser, getStudentHomeworkAssignments } from "@/modules/homework/data-access"
+import { getStudentHomeworkAssignments } from "@/modules/homework/data-access"
+import { getCurrentStudentUser } from "@/modules/users/data-access"
 import { Inbox } from "lucide-react"
 
 export const dynamic = "force-dynamic"
@@ -39,7 +40,7 @@ const getActionVariant = (status: string): "default" | "secondary" | "outline" =
 const isAnswered = (status: string) => status === "submitted" || status === "graded"
 
 export default async function StudentAssignmentsPage() {
-  const student = await getDemoStudentUser()
+  const student = await getCurrentStudentUser()
 
   if (!student) {
     return (