feat(linear): add --type and --exclude-type flags for sync filtering (#1205)

* feat(linear): add --type and --exclude-type flags for sync filtering

Add type filtering support to `bd linear sync --push` to allow users to
control which issue types are synced to Linear.

New flags:
- --type: Only sync issues matching these types (e.g., --type=task,feature)
- --exclude-type: Exclude issues of these types (e.g., --exclude-type=wisp)

Use cases:
- Sync only work items (tasks, features, bugs) while excluding internal
  telemetry (wisps, messages)
- Push only specific issue types to Linear

Fixes #1204

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

* fix(linear): update test to match new doPushToLinear signature

---------

Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>

cmd/bd/linear_test.go

@@ -1220,7 +1220,7 @@ func TestDoPushToLinearPreferLocalForcesUpdate(t *testing.T) {
 	})
 
 	forceUpdateIDs := map[string]bool{issue.ID: true}
-	stats, err := doPushToLinear(ctx, false, false, true, forceUpdateIDs, nil)
+	stats, err := doPushToLinear(ctx, false, false, true, forceUpdateIDs, nil, nil, nil)
 	if err != nil {
 		t.Fatalf("doPushToLinear failed: %v", err)
 	}