ci: skip smart E2E selection for PRs targeting stable branch (#30247)

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## **Description**

Extends the existing release/* skip logic in the Smart E2E Selection
action to also skip AI-driven test selection when a PR targets stable.
PRs to stable (like hotfixes) should always run the full E2E suite, same
as release branches.

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## **Changelog**

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CHANGELOG entry:

## **Related issues**

Fixes:

## **Manual testing steps**

```gherkin
Feature: my feature name

  Scenario: user [verb for user action]
    Given [describe expected initial app state]

    When user [verb for user action]
    Then [describe expected outcome]
```

## **Screenshots/Recordings**

<!-- If applicable, add screenshots and/or recordings to visualize the
before and after of your change. -->

### **Before**

<!-- [screenshots/recordings] -->

### **After**

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## **Pre-merge author checklist**

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Unchecked boxes are ambiguous: they are not an implicit "N/A" and they
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- [ ] I've followed [MetaMask Contributor
Docs](https://github.com/MetaMask/contributor-docs) and [MetaMask Mobile
Coding
Standards](https://github.com/MetaMask/metamask-mobile/blob/main/.github/guidelines/CODING_GUIDELINES.md).
- [ ] I've completed the PR template to the best of my ability
- [ ] I've included tests if applicable
- [ ] I've documented my code using [JSDoc](https://jsdoc.app/) format
if applicable
- [ ] I've applied the right labels on the PR (see [labeling
guidelines](https://github.com/MetaMask/metamask-mobile/blob/main/.github/guidelines/LABELING_GUIDELINES.md)).
Not required for external contributors.

#### Performance checks (if applicable)

- [ ] I've tested on Android
  - Ideally on a mid-range device; emulator is acceptable
- [ ] I've tested with a power user scenario
- Use these [power-user
SRPs](https://consensyssoftware.atlassian.net/wiki/spaces/TL1/pages/edit-v2/401401446401?draftShareId=9d77e1e1-4bdc-4be1-9ebb-ccd916988d93)
to import wallets with many accounts and tokens
- [ ] I've instrumented key operations with Sentry traces for production
performance metrics
- See [`trace()`](/app/util/trace.ts) for usage and
[`addToken`](/app/components/Views/AddAsset/components/AddCustomToken/AddCustomToken.tsx#L274)
for an example

For performance guidelines and tooling, see the [Performance
Guide](https://consensyssoftware.atlassian.net/wiki/spaces/TL1/pages/400085549067/Performance+Guide+for+Engineers).

## **Pre-merge reviewer checklist**

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checklist: an
unchecked box is ambiguous, a checked box means the reviewer consciously
assessed that responsibility. See `docs/readme/ready-for-review.md`.
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- [ ] I've manually tested the PR (e.g. pull and build branch, run the
app, test code being changed).
- [ ] I confirm that this PR addresses all acceptance criteria described
in the ticket it closes and includes the necessary testing evidence such
as recordings and or screenshots.

<!-- CURSOR_SUMMARY -->
---

> [!NOTE]
> **Low Risk**
> Low risk CI-only change that extends existing release-branch
exemptions to the `stable` branch; impact is limited to which E2E suites
run and whether `pr-not-ready-for-e2e` is auto-applied.
> 
> **Overview**
> Extends the existing release-branch CI behavior to the `stable`
branch.
> 
> The `smart-e2e-selection` composite action now skips AI suite
selection (falling back to running the full E2E suite) when the PR base
ref is `release/*` **or** `stable`, and updates skip messaging
accordingly. The auto-label workflow for `pr-not-ready-for-e2e` also
ignores PRs targeting `stable`, and the E2E decision tree docs are
updated to reflect these exemptions.
> 
> <sup>Reviewed by [Cursor Bugbot](https://cursor.com/bugbot) for commit
0966726. Bugbot is set up for automated
code reviews on this repo. Configure
[here](https://www.cursor.com/dashboard/bugbot).</sup>
<!-- /CURSOR_SUMMARY -->

Author: jvbriones

.github/actions/smart-e2e-selection/action.yml

@@ -27,7 +27,7 @@ inputs:
     required: false
     default: 'false'
   base-ref:
-    description: 'PR base branch ref passed to the AI analysis script for diff comparison. When release/*, AI selection is skipped and the full E2E suite is selected.'
+    description: 'PR base branch ref passed to the AI analysis script for diff comparison. When release/* or stable, AI selection is skipped and the full E2E suite is selected.'
     required: false
     default: ''
 outputs:
@@ -57,15 +57,15 @@ runs:
           echo "⏭️ SKIP=true due to 'skip-smart-e2e-selection' label on PR"
         fi
 
-    - name: Check release target branch (full E2E, no AI selection)
+    - name: Check release or stable target branch (full E2E, no AI selection)
       id: check-release-target
       shell: bash
       run: |
         echo "SKIP=false" >> "$GITHUB_OUTPUT"
         BASE='${{ inputs.base-ref }}'
-        if [[ -n "$BASE" && "$BASE" == release/* ]]; then
+        if [[ -n "$BASE" && ( "$BASE" == release/* || "$BASE" == "stable" ) ]]; then
           echo "SKIP=true" >> "$GITHUB_OUTPUT"
-          echo "⏭️ Base branch is release/* — skipping AI E2E selection; full E2E suite will run"
+          echo "⏭️ Base branch is release/* or stable — skipping AI E2E selection; full E2E suite will run"
         fi
 
     - name: Checkout for PR analysis
@@ -142,9 +142,9 @@ runs:
           echo "SKIP_REASON=skip-smart-e2e-selection label found" >> "$GITHUB_OUTPUT"
           echo "ai_confidence=100" >> "$GITHUB_OUTPUT"
         elif [[ "${{ steps.check-release-target.outputs.SKIP }}" == "true" ]]; then
-          echo "⏭️ Skipping AI analysis - PR targets a release branch (release/*)"
+          echo "⏭️ Skipping AI analysis - PR targets a release or stable branch"
           echo "SKIPPED=true" >> "$GITHUB_OUTPUT"
-          echo "SKIP_REASON=PR targets a release branch (release/*)" >> "$GITHUB_OUTPUT"
+          echo "SKIP_REASON=PR targets a release or stable branch (release/* or stable)" >> "$GITHUB_OUTPUT"
           echo "ai_confidence=100" >> "$GITHUB_OUTPUT"
         else
           echo "✅ Running AI analysis for PR #$PR_NUMBER"

.github/guidelines/E2E_DECISION_TREE.md

@@ -56,7 +56,7 @@ Flakiness detection is applied to modified E2E test files in PRs:
 
 ## Release branches
 
-PRs to release branches (cherry-picked from main) are exempt from the following:
+PRs to release branches (cherry-picks from main to release/\* branches and PRs to stable branch) are exempt from the following:
 
 - Label `pr-not-ready-for-e2e` is not applied
 - Smart AI E2E selection is skipped - all E2E suites are run (if changes are not ignorable-only, e.g. only docs)

.github/workflows/auto-label-not-ready-for-e2e.yml

@@ -7,6 +7,7 @@ on:
     types: [opened]
     branches-ignore:
       - 'release/**'
+      - 'stable'
 
 jobs:
   add-label: