ci: run regression tests, type checks and the web build on pull requests (#569)

The full non-E2E suite (`bun run test`) only ran inside the release
workflow, and pull requests only built the Docker image, so a failing test
or type error surfaced at release time. A new Test workflow runs on every
pull request and push to main (Markdown and docs-only changes excluded):

- "Type check and build": `bun run typecheck`, `bun run typecheck:mobile`
  and `bun run build:web`;
- "Regression tests": `bun run test` (bulk and integration suites).

It uses the Bun version pinned in package.json, retries `bun install` like
the other workflows, cancels superseded runs, reads the repository only,
and is limited to this repository so deployment forks spend no runners.

.github/workflows/test.yml

@@ -0,0 +1,91 @@
+name: Test
+
+# Runs the non-E2E regression suite, type checks and the web build for every
+# pull request and every push to main, so failures surface before a release
+# instead of in the release workflow.
+on:
+  pull_request:
+    paths-ignore:
+      - "**/*.md"
+      - "docs/**"
+  push:
+    branches:
+      - main
+    paths-ignore:
+      - "**/*.md"
+      - "docs/**"
+  workflow_dispatch:
+
+permissions:
+  contents: read
+
+concurrency:
+  group: edgeever-test-${{ github.event.pull_request.number || github.ref }}
+  cancel-in-progress: true
+
+jobs:
+  checks:
+    # Forks that deploy their own copy do not spend runners on this; pull
+    # requests opened against this repository still run here.
+    if: github.repository == 'tianma-if/edgeever'
+    name: Type check and build
+    runs-on: ubuntu-latest
+    timeout-minutes: 20
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v5
+
+      - name: Set up Bun
+        uses: oven-sh/setup-bun@v2
+        with:
+          bun-version-file: package.json
+
+      - name: Install dependencies
+        run: |
+          for attempt in 1 2 3; do
+            if bun install --frozen-lockfile; then
+              exit 0
+            fi
+            if [[ "$attempt" = "3" ]]; then
+              exit 1
+            fi
+            sleep "$((15 * attempt))"
+          done
+
+      - name: Type check
+        run: bun run typecheck
+
+      - name: Type check mobile
+        run: bun run typecheck:mobile
+
+      - name: Build web
+        run: bun run build:web
+
+  tests:
+    if: github.repository == 'tianma-if/edgeever'
+    name: Regression tests
+    runs-on: ubuntu-latest
+    timeout-minutes: 30
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v5
+
+      - name: Set up Bun
+        uses: oven-sh/setup-bun@v2
+        with:
+          bun-version-file: package.json
+
+      - name: Install dependencies
+        run: |
+          for attempt in 1 2 3; do
+            if bun install --frozen-lockfile; then
+              exit 0
+            fi
+            if [[ "$attempt" = "3" ]]; then
+              exit 1
+            fi
+            sleep "$((15 * attempt))"
+          done
+
+      - name: Run regression tests
+        run: bun run test