feat(ready): add --type flag for filtering by issue type (gt-ktf3)

Enables bd ready --type=merge-request for MQ integration.
The Engineer can now query for ready merge-requests.

Files changed:
- cmd/bd/ready.go: Add -t/--type flag
- internal/types/types.go: Add Type field to WorkFilter
- internal/rpc/protocol.go: Add Type to ReadyArgs
- internal/storage/sqlite/ready.go: Filter by issue_type column

internal/rpc/protocol.go

@@ -214,6 +214,7 @@ type ReadyArgs struct {
 	Assignee   string   `json:"assignee,omitempty"`
 	Unassigned bool     `json:"unassigned,omitempty"`
 	Priority   *int     `json:"priority,omitempty"`
+	Type       string   `json:"type,omitempty"`
 	Limit      int      `json:"limit,omitempty"`
 	SortPolicy string   `json:"sort_policy,omitempty"`
 	Labels     []string `json:"labels,omitempty"`

internal/storage/sqlite/ready.go

@@ -27,6 +27,12 @@ func (s *SQLiteStorage) GetReadyWork(ctx context.Context, filter types.WorkFilte
 		args = append(args, filter.Status)
 	}
 
+	// Filter by issue type (gt-ktf3: MQ integration)
+	if filter.Type != "" {
+		whereClauses = append(whereClauses, "i.issue_type = ?")
+		args = append(args, filter.Type)
+	}
+
 	if filter.Priority != nil {
 		whereClauses = append(whereClauses, "i.priority = ?")
 		args = append(args, *filter.Priority)

internal/types/types.go

@@ -478,6 +478,7 @@ func (s SortPolicy) IsValid() bool {
 // WorkFilter is used to filter ready work queries
 type WorkFilter struct {
 	Status     Status
+	Type       string     // Filter by issue type (task, bug, feature, epic, merge-request, etc.)
 	Priority   *int
 	Assignee   *string
 	Unassigned bool       // Filter for issues with no assignee