chore: remove GitHub workflows

Removed .github/workflows directory as the application is now fully
static and deployment workflows are no longer needed. The app can be
deployed to any static hosting platform without CI/CD pipelines.

Static deployment options:
- Vercel, Netlify, Cloudflare Pages (zero config)
- GitHub Pages, S3, CDN
- Self-hosted nginx/Apache
- Docker (optional)

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

.github/workflows/docker.yml

@@ -1,75 +0,0 @@
-name: Docker Build & Push
-
-on:
-  push:
-    branches:
-      - main
-    tags:
-      - 'v*.*.*'
-  pull_request:
-    branches:
-      - main
-
-env:
-  REGISTRY: ghcr.io
-  IMAGE_NAME: ${{ github.repository }}
-
-jobs:
-  build-and-push:
-    runs-on: ubuntu-latest
-    permissions:
-      contents: read
-      packages: write
-      id-token: write
-      attestations: write
-
-    steps:
-      - name: Checkout repository
-        uses: actions/checkout@v4
-
-      - name: Set up Docker Buildx
-        uses: docker/setup-buildx-action@v3
-
-      - name: Log in to GitHub Container Registry
-        if: github.event_name != 'pull_request'
-        uses: docker/login-action@v3
-        with:
-          registry: ${{ env.REGISTRY }}
-          username: ${{ github.actor }}
-          password: ${{ secrets.GITHUB_TOKEN }}
-
-      - name: Extract metadata (tags, labels)
-        id: meta
-        uses: docker/metadata-action@v5
-        with:
-          images: ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}
-          tags: |
-            type=ref,event=branch
-            type=ref,event=pr
-            type=semver,pattern={{version}}
-            type=semver,pattern={{major}}.{{minor}}
-            type=semver,pattern={{major}}
-            type=sha,prefix={{branch}}-
-            type=raw,value=latest,enable={{is_default_branch}}
-
-      - name: Build and push Docker image
-        id: build-and-push
-        uses: docker/build-push-action@v5
-        with:
-          context: .
-          platforms: linux/amd64,linux/arm64
-          push: ${{ github.event_name != 'pull_request' }}
-          tags: ${{ steps.meta.outputs.tags }}
-          labels: ${{ steps.meta.outputs.labels }}
-          cache-from: type=gha
-          cache-to: type=gha,mode=max
-          build-args: |
-            NEXT_PUBLIC_API_URL=${{ vars.NEXT_PUBLIC_API_URL || 'http://localhost:3001' }}
-
-      - name: Generate artifact attestation
-        if: github.event_name != 'pull_request'
-        uses: actions/attest-build-provenance@v1
-        with:
-          subject-name: ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}
-          subject-digest: ${{ steps.build-and-push.outputs.digest }}
-          push-to-registry: true