Add workflow to label PRs with merge conflicts (#342)

* fix(#65): request POST_NOTIFICATIONS runtime permission on Android 13+

On API 33+ the manifest declaration alone is not enough — the app must
request POST_NOTIFICATIONS via ActivityResultContracts.RequestPermission
at runtime before it can show any notification, including the foreground
service notification from ChatNotificationService.

- Added rememberLauncherForActivityResult for POST_NOTIFICATIONS
- Added LaunchedEffect(Unit) that fires the permission request on first
  composition when running on API 33+ and permission is not yet granted
- The next lifecycle event (ON_STOP → NotificationHelper.start) picks
  up the permission if granted

* fix: add missing import android.os.Build for POST_NOTIFICATIONS permission check

* fix: add missing import for rememberLauncherForActivityResult (androidx.activity.compose)

* Add GitHub workflow to check PR for linked issue

* Add workflow to label PRs with merge conflicts

* Remove pr-issue-check.yml, keep only merge-conflict-label workflow

* Remove issue-tag.yml, keep only merge-conflict-label workflow in PR

---------

Co-authored-by: M57 <hy4ri@users.noreply.github.com>
Co-authored-by: Hermes Agent <hermes@m57.local>
Co-authored-by: Hermes Agent <hermes@agent.local>

.github/workflows/merge-conflict-label.yml

@@ -0,0 +1,56 @@
+name: Label PR merge conflicts
+
+on:
+  pull_request:
+    types: [opened, synchronize, reopened, ready_for_review]
+
+jobs:
+  label-conflict:
+    runs-on: ubuntu-latest
+    permissions:
+      pull-requests: write
+      contents: read
+    steps:
+      - name: Get PR data and label conflicts
+        uses: actions/github-script@v7
+        with:
+          script: |
+            const pr = context.payload.pull_request;
+            const prNumber = pr.number;
+            const repo = context.repo;
+
+            // Fetch PR details to get mergeable_state
+            const { data: prData } = await github.rest.pulls.get({
+              ...repo,
+              pull_number: prNumber
+            });
+
+            const mergeableState = prData.mergeable_state; // clean, dirty, blocked, unstable
+            const hasConflict = mergeableState === 'dirty';
+
+            const labelName = 'merge-conflict';
+
+            // Get current labels
+            const { data: labels } = await github.rest.issues.listLabelsOnIssue({
+              ...repo,
+              issue_number: prNumber
+            });
+            const hasLabel = labels.some(l => l.name === labelName);
+
+            if (hasConflict && !hasLabel) {
+              console.log(`PR #${prNumber} has merge conflicts. Adding label '${labelName}'.`);
+              await github.rest.issues.addLabels({
+                ...repo,
+                issue_number: prNumber,
+                labels: [labelName]
+              });
+            } else if (!hasConflict && hasLabel) {
+              console.log(`PR #${prNumber} no longer has merge conflicts. Removing label '${labelName}'.`);
+              await github.rest.issues.removeLabel({
+                ...repo,
+                issue_number: prNumber,
+                name: labelName
+              });
+            } else {
+              console.log(`PR #${prNumber}: conflict=${hasConflict}, label=${hasLabel}. No change needed.`);
+            }