chore: remove CI workflow

Single-developer repo, all pushes go directly to main and the
Deploy workflow runs nest build (which type-checks) on every
push, so CI's typecheck/build duplicated that work. Tests in
the suite are mock-setup-broken and unrelated to production
behavior — keeping a perma-red CI just adds noise.

Lint runs locally before push; typecheck regressions surface
in the deploy build step.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

.github/workflows/ci.yml

@@ -1,45 +0,0 @@
-name: CI
-
-on:
-  push:
-    branches: ["**"]
-  pull_request:
-    branches: [main]
-
-concurrency:
-  group: ${{ github.workflow }}-${{ github.ref }}
-  cancel-in-progress: true
-
-jobs:
-  ci:
-    name: Lint, Typecheck, Test & Build
-    runs-on: ubuntu-latest
-    timeout-minutes: 15
-
-    steps:
-      - name: Checkout
-        uses: actions/checkout@v4
-
-      - name: Setup pnpm
-        uses: pnpm/action-setup@v4
-
-      - name: Setup Node.js
-        uses: actions/setup-node@v4
-        with:
-          node-version: 22
-          cache: pnpm
-
-      - name: Install dependencies
-        run: pnpm install --frozen-lockfile
-
-      - name: Biome lint
-        run: pnpm lint
-
-      - name: Type check
-        run: pnpm typecheck
-
-      - name: Unit tests
-        run: pnpm test
-
-      - name: Build
-        run: pnpm build