feat: add close: label group, type:enhancement, and legacy label migration

- Add CLOSE_LABELS: close:fixed, close:wont-fix, close:duplicate,
  close:question-answered
- Add type:enhancement to TYPE_LABELS
- Remove standalone 'bug' from SIGNAL_LABELS (replaced by type:bug)
- Add migration step to rename legacy labels (bug, question, enhancement)
  to their type: equivalents — rename preserves issue associations

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: EMaher

.github/workflows/issue-labels-sync.yml

@@ -86,6 +86,7 @@ jobs:
 
             const TYPE_LABELS = [
               { name: 'type:feature', color: 'DDD1F2', description: 'New capability' },
+              { name: 'type:enhancement', color: 'A2EEEF', description: 'Improvement to existing functionality' },
               { name: 'type:bug', color: 'FF0422', description: 'Something broken' },
               { name: 'type:question', color: 'D876E3', description: 'Questions about usage or behavior' },
               { name: 'type:documentation', color: '0075CA', description: 'Documentation issues or requests' },
@@ -95,6 +96,13 @@ jobs:
               { name: 'type:epic', color: 'CC4455', description: 'Parent issue that decomposes into sub-issues' }
             ];
 
+            const CLOSE_LABELS = [
+              { name: 'close:fixed', color: '0E8A16', description: 'Fixed by a previous PR or release' },
+              { name: 'close:wont-fix', color: 'FFFFFF', description: 'Will not be addressed' },
+              { name: 'close:duplicate', color: 'CFD3D7', description: 'Duplicate of another issue' },
+              { name: 'close:question-answered', color: 'D876E3', description: 'Question has been answered' }
+            ];
+
             const EFFORT_LABELS = [
               { name: 'effort:S', color: '0E8A16', description: 'Small effort (< 1 day)' },
               { name: 'effort:M', color: 'FBCA04', description: 'Medium effort (1-3 days)' },
@@ -104,7 +112,6 @@ jobs:
 
             // High-signal labels — these MUST visually dominate all others
             const SIGNAL_LABELS = [
-              { name: 'bug', color: 'FF0422', description: 'Something isn\'t working' },
               { name: 'feedback', color: '00E5FF', description: 'User feedback — high signal, needs attention' }
             ];
 
@@ -144,15 +151,47 @@ jobs:
               });
             }
 
-            // Add go:, release:, type:, effort:, priority:, high-signal, and lifecycle labels
+            // Add go:, release:, type:, close:, effort:, priority:, high-signal, and lifecycle labels
             labels.push(...GO_LABELS);
             labels.push(...RELEASE_LABELS);
             labels.push(...TYPE_LABELS);
+            labels.push(...CLOSE_LABELS);
             labels.push(...EFFORT_LABELS);
             labels.push(...PRIORITY_LABELS);
             labels.push(...SIGNAL_LABELS);
             labels.push(...LIFECYCLE_LABELS);
 
+            // Migrate legacy labels → type: equivalents (rename preserves issue associations)
+            const MIGRATIONS = [
+              { from: 'bug', to: 'type:bug' },
+              { from: 'question', to: 'type:question' },
+              { from: 'enhancement', to: 'type:enhancement' }
+            ];
+
+            for (const { from, to } of MIGRATIONS) {
+              try {
+                await github.rest.issues.getLabel({
+                  owner: context.repo.owner,
+                  repo: context.repo.repo,
+                  name: from
+                });
+                // Old label exists — rename it (this moves all issues to the new name)
+                await github.rest.issues.updateLabel({
+                  owner: context.repo.owner,
+                  repo: context.repo.repo,
+                  name: from,
+                  new_name: to
+                });
+                core.info(`Migrated label: ${from} → ${to}`);
+              } catch (err) {
+                if (err.status === 404) {
+                  core.info(`Legacy label "${from}" not found — no migration needed`);
+                } else {
+                  core.warning(`Failed to migrate ${from}: ${err.message}`);
+                }
+              }
+            }
+
             // Sync labels (create or update)
             for (const label of labels) {
               try {