ci) add gitea actions and refresh readme (#1)

Summary:\n- replace scaffold README with project-specific setup, testing, Docker, and CI docs\n- add PR workflow to run lint, unit tests, app build, and Docker build\n- add main-branch workflow to build and push Docker images to Gitea registry\n\nNotes:\n- publish workflow expects REGISTRY_USERNAME and REGISTRY_PASSWORD repository secrets\n- image tags pushed: latest and short commit SHA\n\nTesting:\n- not run locally (workflows execute in Gitea Actions)
Reviewed-on: CampbellWireless/trips#1
Co-authored-by: Shaun Campbell <shaun@campbellwireless.net>
Co-committed-by: Shaun Campbell <shaun@campbellwireless.net>

.gitea/workflows/pr-checks.yml

@@ -0,0 +1,44 @@
+name: PR Checks
+
+on:
+  pull_request:
+
+jobs:
+  lint-test-and-docker-build:
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout
+        env:
+          REPO_URL: https://cloud.campbellwireless.net/git/${{ github.repository }}.git
+        run: |
+          set -eux
+          git init .
+          git remote add origin "$REPO_URL"
+          auth="$(printf '%s' '${{ github.actor }}:${{ secrets.GITHUB_TOKEN }}' | base64 | tr -d '\n')"
+          git config --local http.https://cloud.campbellwireless.net/.extraheader "AUTHORIZATION: basic $auth"
+          git fetch --prune --no-recurse-submodules origin +refs/heads/*:refs/remotes/origin/* +refs/tags/*:refs/tags/*
+          git checkout --detach "${{ github.sha }}"
+
+      - name: Setup Bun
+        uses: oven-sh/setup-bun@v2
+        with:
+          bun-version: '1.3.3'
+
+      - name: Install dependencies
+        run: bun install --frozen-lockfile
+
+      - name: Generate SvelteKit files
+        run: bun run prepare
+
+      - name: Lint
+        run: bun run lint
+
+      - name: Unit tests
+        run: bunx --bun svelte-kit sync && bunx --bun vitest run --maxWorkers=1
+
+      - name: Build app
+        run: bun run build
+
+      - name: Build Docker image
+        run: docker build --file Dockerfile --tag trips:pr-${{ github.sha }} .