fix: CI/CD — replace broken bun --cwd with turbo --filter for web build

The deploy workflow used 'bun --cwd apps/web run build' which does NOT
work — 'bun run' doesn't support --cwd flag. Bun prints usage and exits
0, making the step silently succeed without building. Fix: use
'bun run build --filter=@mcpedia/web' (turbo workspace filtering).

Also bump actions/checkout@v4→v5 to resolve Node 20 deprecation warning.

.github/workflows/ci.yml

@@ -17,7 +17,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout
-        uses: actions/checkout@v4
+        uses: actions/checkout@v5
 
       - name: Set up Bun
         uses: oven-sh/setup-bun@v2

.github/workflows/deploy.yml

@@ -17,7 +17,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout
-        uses: actions/checkout@v4
+        uses: actions/checkout@v5
 
       - name: Set up Bun
         uses: oven-sh/setup-bun@v2
@@ -31,7 +31,7 @@ jobs:
         run: bun run typecheck
 
       - name: Build web app
-        run: bun --cwd apps/web run build
+        run: bun run build --filter=@mcpedia/web
 
       - name: Deploy to VPS over SSH
         uses: appleboy/ssh-action@v1
@@ -46,7 +46,7 @@ jobs:
             cd /home/code/mcpedia
             git pull origin main
             /home/code/.bun/bin/bun install --frozen-lockfile
-            /home/code/.bun/bin/bun --cwd apps/web run build
+            /home/code/.bun/bin/bun run build --filter=@mcpedia/web
             /home/code/.bun/bin/bun run scripts/indexer.ts
             sudo systemctl restart mcpedia-web mcpedia-api mcpedia-mcp mcpedia-worker
             sleep 3