ci: skip tests when PR has no code changes (#13034)

### What this PR does

Before this PR:
All three CI matrix tasks (`basic-checks`, `general-test`,
`render-test`) ran on every PR regardless of what files changed.

After this PR:
- Tests are skipped on PRs that only modify non-code files (e.g., docs,
CI configs, markdown). `basic-checks` (lint, format, typecheck, i18n,
skills) always runs.
- `general-test` and `render-test` are split into independent jobs with
granular path filters:
- `src/main/**`, `src/preload/**`, `scripts/**` → only triggers
`general-test`
  - `src/renderer/**` → only triggers `render-test`
  - `packages/**`, `tests/**`, config/dependency files → triggers both

### Why we need it and why it was done in this way

Non-code PRs (documentation updates, CI workflow changes, maintenance
files) do not need test suites to run, saving CI minutes and reducing
feedback latency. Granular filtering further reduces waste — a
renderer-only change no longer waits for main process tests and vice
versa.

The following tradeoffs were made:
- Tests always run on `push` to `main` and `workflow_dispatch` for
safety, even if the change is non-code.
- `packages/**` changes trigger both test jobs since packages may be
consumed by either process.

The following alternatives were considered:
- Using `paths` / `paths-ignore` on the workflow trigger level, but that
would skip the entire workflow including `basic-checks`.
- Keeping a single `tests` matrix job, but separate jobs allow job-level
`if` conditions for independent skipping and clearer GitHub UI feedback.

### Breaking changes

None.

### Special notes for your reviewer

- Uses `dorny/paths-filter@v3` for change detection with three filter
groups: `main`, `renderer`, `shared`.
- The `changes` job is lightweight (checkout + filter only, no `pnpm
install`).
- The `notify` job dependencies updated from `[ci,
skills-check-windows]` to `[basic-checks, general-test, render-test,
skills-check-windows]`.
- `tests/**` is included in the `shared` filter so test-only PRs still
trigger test jobs.

### Checklist

- [x] PR: The PR description is expressive enough and will help future
contributors
- [x] Code: [Write code that humans can
understand](https://en.wikiquote.org/wiki/Martin_Fowler#code-for-humans)
and [Keep it simple](https://en.wikipedia.org/wiki/KISS_principle)
- [x] Refactor: You have [left the code cleaner than you found it (Boy
Scout
Rule)](https://learning.oreilly.com/library/view/97-things-every/9780596809515/ch08.html)
- [x] Upgrade: Impact of this change on upgrade flows was considered and
addressed if required
- [ ] Documentation: A [user-guide update](https://docs.cherry-ai.com)
was considered and is present (link) or not required. You want a
user-guide update if it's a user facing feature.

### Release note

```release-note
NONE
```

---------

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

.github/workflows/ci.yml

@@ -16,12 +16,41 @@ on:
     types: [ready_for_review, synchronize, opened, edited]
 
 jobs:
-  ci:
+  changes:
+    runs-on: ubuntu-latest
+    if: github.event_name == 'push' || github.event_name == 'workflow_dispatch' || github.event.pull_request.draft == false
+    outputs:
+      main: ${{ steps.filter.outputs.main }}
+      renderer: ${{ steps.filter.outputs.renderer }}
+      shared: ${{ steps.filter.outputs.shared }}
+    steps:
+      - name: Check out Git repository
+        uses: actions/checkout@v6
+
+      - name: Detect code changes
+        id: filter
+        uses: dorny/paths-filter@v3
+        with:
+          filters: |
+            main:
+              - 'src/main/**'
+              - 'src/preload/**'
+              - 'scripts/**'
+            renderer:
+              - 'src/renderer/**'
+            shared:
+              - 'packages/**'
+              - 'tests/**'
+              - 'package.json'
+              - 'pnpm-lock.yaml'
+              - 'pnpm-workspace.yaml'
+              - 'tsconfig*.json'
+              - 'electron.vite.config.ts'
+              - 'vitest.config.ts'
+              - 'patches/**'
+
+  basic-checks:
     runs-on: ubuntu-latest
-    strategy:
-      fail-fast: false
-      matrix:
-        task: [basic-checks, general-test, render-test]
     env:
       CI: true
     if: github.event_name == 'push' || github.event_name == 'workflow_dispatch' || github.event.pull_request.draft == false
@@ -55,47 +84,114 @@ jobs:
         run: pnpm install
 
       - name: Lint Check
-        if: matrix.task == 'basic-checks'
         run: pnpm test:lint
 
       - name: Format Check
-        if: matrix.task == 'basic-checks'
         run: pnpm format:check
 
       - name: Type Check
-        if: matrix.task == 'basic-checks'
         run: pnpm typecheck
 
       - name: i18n Check
-        if: matrix.task == 'basic-checks'
         run: pnpm i18n:check
 
       - name: Hardcoded Strings Check
-        if: matrix.task == 'basic-checks'
         run: pnpm i18n:hardcoded:strict
 
       - name: Skills Check
-        if: matrix.task == 'basic-checks'
         run: pnpm skills:check
 
+  general-test:
+    runs-on: ubuntu-latest
+    needs: changes
+    if: >-
+      needs.changes.outputs.main == 'true' ||
+      needs.changes.outputs.shared == 'true' ||
+      github.event_name == 'push' ||
+      github.event_name == 'workflow_dispatch'
+    env:
+      CI: true
+
+    steps:
+      - name: Check out Git repository
+        uses: actions/checkout@v6
+
+      - name: Install Node.js
+        uses: actions/setup-node@v6
+        with:
+          node-version: 22
+
+      - name: Install pnpm
+        uses: pnpm/action-setup@v4
+
+      - name: Get pnpm store directory
+        id: pnpm-cache
+        shell: bash
+        run: echo "STORE_PATH=$(pnpm store path --silent)" >> $GITHUB_OUTPUT
+
+      - name: Cache pnpm dependencies
+        uses: actions/cache@v5
+        with:
+          path: ${{ steps.pnpm-cache.outputs.STORE_PATH }}
+          key: ${{ runner.os }}-pnpm-${{ hashFiles('**/pnpm-lock.yaml') }}
+          restore-keys: |
+            ${{ runner.os }}-pnpm-
+
+      - name: Install Dependencies
+        run: pnpm install
+
       - name: Main Process Test
-        if: matrix.task == 'general-test'
         run: pnpm test:main
 
       - name: AI Core Test
-        if: matrix.task == 'general-test'
         run: pnpm test:aicore
 
       - name: Shared Package Test
-        if: matrix.task == 'general-test'
         run: pnpm test:shared
 
       - name: Scripts Test
-        if: matrix.task == 'general-test'
         run: pnpm test:scripts
 
+  render-test:
+    runs-on: ubuntu-latest
+    needs: changes
+    if: >-
+      needs.changes.outputs.renderer == 'true' ||
+      needs.changes.outputs.shared == 'true' ||
+      github.event_name == 'push' ||
+      github.event_name == 'workflow_dispatch'
+    env:
+      CI: true
+
+    steps:
+      - name: Check out Git repository
+        uses: actions/checkout@v6
+
+      - name: Install Node.js
+        uses: actions/setup-node@v6
+        with:
+          node-version: 22
+
+      - name: Install pnpm
+        uses: pnpm/action-setup@v4
+
+      - name: Get pnpm store directory
+        id: pnpm-cache
+        shell: bash
+        run: echo "STORE_PATH=$(pnpm store path --silent)" >> $GITHUB_OUTPUT
+
+      - name: Cache pnpm dependencies
+        uses: actions/cache@v5
+        with:
+          path: ${{ steps.pnpm-cache.outputs.STORE_PATH }}
+          key: ${{ runner.os }}-pnpm-${{ hashFiles('**/pnpm-lock.yaml') }}
+          restore-keys: |
+            ${{ runner.os }}-pnpm-
+
+      - name: Install Dependencies
+        run: pnpm install
+
       - name: Renderer Test
-        if: matrix.task == 'render-test'
         run: pnpm test:renderer
 
   skills-check-windows:
@@ -136,8 +232,8 @@ jobs:
 
   notify:
     runs-on: ubuntu-latest
-    needs: [ci, skills-check-windows]
-    if: always() && (needs.ci.result == 'failure' || needs.skills-check-windows.result == 'failure') && github.event_name == 'push' && github.ref == 'refs/heads/main'
+    needs: [basic-checks, general-test, render-test, skills-check-windows]
+    if: always() && (needs.basic-checks.result == 'failure' || needs.general-test.result == 'failure' || needs.render-test.result == 'failure' || needs.skills-check-windows.result == 'failure') && github.event_name == 'push' && github.ref == 'refs/heads/main'
     steps:
       - name: Check out Git repository
         uses: actions/checkout@v6