Implement centralized logging with RMABLogger

Replaces scattered console statements with a unified RMABLogger across backend API routes and services. Adds LOG_LEVEL-based filtering, job-aware database persistence, and context-based logging. Updates documentation to describe the new logging system and usage patterns. Also documents qBittorrent CSRF header fix

src/app/api/admin/users/[id]/approve/route.ts

@@ -6,6 +6,9 @@
 import { NextRequest, NextResponse } from 'next/server';
 import { requireAuth, requireAdmin, AuthenticatedRequest } from '@/lib/middleware/auth';
 import { prisma } from '@/lib/db';
+import { RMABLogger } from '@/lib/utils/logger';
+
+const logger = RMABLogger.create('API.Admin.Users.Approve');
 
 export async function POST(
   request: NextRequest,
@@ -64,7 +67,7 @@ export async function POST(
           });
         }
       } catch (error) {
-        console.error('[Admin] Failed to approve/reject user:', error);
+        logger.error('Failed to approve/reject user', { error: error instanceof Error ? error.message : String(error) });
         return NextResponse.json(
           { error: 'Failed to process user approval' },
           { status: 500 }

src/app/api/admin/users/[id]/route.ts

@@ -6,6 +6,9 @@
 import { NextRequest, NextResponse } from 'next/server';
 import { requireAuth, requireAdmin, AuthenticatedRequest } from '@/lib/middleware/auth';
 import { prisma } from '@/lib/db';
+import { RMABLogger } from '@/lib/utils/logger';
+
+const logger = RMABLogger.create('API.Admin.Users');
 
 export async function PUT(
   request: NextRequest,
@@ -89,7 +92,7 @@ export async function PUT(
 
         return NextResponse.json({ user: updatedUser });
       } catch (error) {
-        console.error('[Admin] Failed to update user:', error);
+        logger.error('Failed to update user', { error: error instanceof Error ? error.message : String(error) });
         return NextResponse.json(
           { error: 'Failed to update user' },
           { status: 500 }
@@ -184,7 +187,7 @@ export async function DELETE(
           message: `User "${targetUser.plexUsername}" has been deleted. Their ${targetUser._count.requests} request(s) have been preserved.`
         });
       } catch (error) {
-        console.error('[Admin] Failed to delete user:', error);
+        logger.error('Failed to delete user', { error: error instanceof Error ? error.message : String(error) });
         return NextResponse.json(
           { error: 'Failed to delete user' },
           { status: 500 }

src/app/api/admin/users/pending/route.ts

@@ -6,6 +6,9 @@
 import { NextRequest, NextResponse } from 'next/server';
 import { requireAuth, requireAdmin, AuthenticatedRequest } from '@/lib/middleware/auth';
 import { prisma } from '@/lib/db';
+import { RMABLogger } from '@/lib/utils/logger';
+
+const logger = RMABLogger.create('API.Admin.Users.Pending');
 
 export async function GET(request: NextRequest) {
   return requireAuth(request, async (req: AuthenticatedRequest) => {
@@ -30,7 +33,7 @@ export async function GET(request: NextRequest) {
 
         return NextResponse.json({ users: pendingUsers });
       } catch (error) {
-        console.error('[Admin] Failed to fetch pending users:', error);
+        logger.error('Failed to fetch pending users', { error: error instanceof Error ? error.message : String(error) });
         return NextResponse.json(
           { error: 'Failed to fetch pending users' },
           { status: 500 }

src/app/api/admin/users/route.ts

@@ -6,6 +6,9 @@
 import { NextRequest, NextResponse } from 'next/server';
 import { requireAuth, requireAdmin, AuthenticatedRequest } from '@/lib/middleware/auth';
 import { prisma } from '@/lib/db';
+import { RMABLogger } from '@/lib/utils/logger';
+
+const logger = RMABLogger.create('API.Admin.Users');
 
 export async function GET(request: NextRequest) {
   return requireAuth(request, async (req: AuthenticatedRequest) => {
@@ -40,7 +43,7 @@ export async function GET(request: NextRequest) {
 
         return NextResponse.json({ users });
       } catch (error) {
-        console.error('[Admin] Failed to fetch users:', error);
+        logger.error('Failed to fetch users', { error: error instanceof Error ? error.message : String(error) });
         return NextResponse.json(
           { error: 'Failed to fetch users' },
           { status: 500 }