Fix: Skip draft releases in update checker

Bug: Pulse was showing update notifications for draft releases because
the update checker didn't filter them out.

The GitHub API returns draft releases in the releases endpoint, and
Pulse was treating them as available updates even though they're not
published yet.

Fix:
- Added Draft field to ReleaseInfo struct
- Added draft filtering in both RC and stable channel logic
- Draft releases are now skipped with debug logging

This prevents users from seeing "Update available" notifications
when maintainers create draft releases during the release workflow.

internal/updates/manager.go

@@ -38,6 +38,7 @@ type ReleaseInfo struct {
 	Name        string    `json:"name"`
 	Body        string    `json:"body"`
 	Prerelease  bool      `json:"prerelease"`
+	Draft       bool      `json:"draft"`
 	PublishedAt time.Time `json:"published_at"`
 	Assets      []struct {
 		Name               string `json:"name"`
@@ -595,6 +596,12 @@ func (m *Manager) getLatestReleaseForChannel(ctx context.Context, channel string
 		var newestStable *ReleaseInfo
 
 		for i := range releases {
+			// Skip draft releases
+			if releases[i].Draft {
+				log.Debug().Str("tag", releases[i].TagName).Msg("Skipping draft release")
+				continue
+			}
+
 			releaseVer, err := ParseVersion(releases[i].TagName)
 			if err != nil {
 				log.Debug().Str("tag", releases[i].TagName).Err(err).Msg("Failed to parse release version")
@@ -665,6 +672,12 @@ func (m *Manager) getLatestReleaseForChannel(ctx context.Context, channel string
 	} else {
 		// For stable channel: find latest non-prerelease
 		for i := range releases {
+			// Skip draft releases
+			if releases[i].Draft {
+				log.Debug().Str("tag", releases[i].TagName).Msg("Skipping draft release")
+				continue
+			}
+
 			if releases[i].Prerelease {
 				continue
 			}