feat(ready,blocked): Add --parent flag for scoping by epic/bead desce… (#743)

* feat(ready,blocked): Add --parent flag for scoping by epic/bead descendants

Add --parent flag to `bd ready` and `bd blocked` CLI commands and MCP tools
to filter results to all descendants of a specific epic or bead.

## Backward Compatibility

- CLI: New optional --parent flag; existing usage unchanged
- RPC: New `blocked` operation added (was missing); existing operations unchanged
- MCP: New optional `parent` parameter; existing calls work as before
- Storage interface: GetBlockedIssues signature changed to accept WorkFilter
  - All callers updated to pass empty filter for existing behavior
  - Empty WorkFilter{} returns identical results to previous implementation

## Implementation Details

SQLite uses recursive CTE to traverse parent-child hierarchy:

    WITH RECURSIVE descendants AS (
        SELECT issue_id FROM dependencies
        WHERE type = 'parent-child' AND depends_on_id = ?
        UNION ALL
        SELECT d.issue_id FROM dependencies d
        JOIN descendants dt ON d.depends_on_id = dt.issue_id
        WHERE d.type = 'parent-child'
    )
    SELECT issue_id FROM descendants

MemoryStorage implements equivalent recursive traversal with visited-set
cycle protection via collectDescendants helper.

Parent filter composes with existing filters (priority, labels, assignee, etc.)
as an additional WHERE clause - all filters are AND'd together.

## RPC Blocked Support

MCP beads_blocked() existed but daemon client raised NotImplementedError.
Added OpBlocked and handleBlocked to enable daemon RPC path, which was
previously broken. Now both CLI and daemon clients work for blocked queries.

## Changes

- internal/types/types.go: Add ParentID *string to WorkFilter
- internal/storage/sqlite/ready.go: Add recursive CTE for parent filtering
- internal/storage/memory/memory.go: Add getAllDescendants/collectDescendants
- internal/storage/storage.go: Update GetBlockedIssues interface signature
- cmd/bd/ready.go: Add --parent flag to ready and blocked commands
- internal/rpc/protocol.go: Add OpBlocked constant and BlockedArgs type
- internal/rpc/server_issues_epics.go: Add handleBlocked RPC handler
- internal/rpc/client.go: Add Blocked client method
- integrations/beads-mcp/: Add BlockedParams model and parent parameter

## Usage

  bd ready --parent bd-abc              # All ready descendants
  bd ready --parent bd-abc --priority 1 # Combined with other filters
  bd blocked --parent bd-abc            # All blocked descendants

## Testing

Added 4 test cases for parent filtering:
- TestParentIDFilterDescendants: Verifies recursive traversal (grandchildren)
- TestParentIDWithOtherFilters: Verifies composition with priority filter
- TestParentIDWithBlockedDescendants: Verifies blocked issues excluded from ready
- TestParentIDEmptyParent: Verifies empty result for childless parent

* fix: Correct blockedCmd indentation and suppress gosec false positive

- Fix syntax error from incorrect indentation in blockedCmd Run function
- Add nolint:gosec comment for GetBlockedIssues SQL formatting (G201)
  The filterSQL variable contains only parameterized WHERE clauses with
  ? placeholders, not user input

internal/rpc/client.go

@@ -333,6 +333,11 @@ func (c *Client) Ready(args *ReadyArgs) (*Response, error) {
 	return c.Execute(OpReady, args)
 }
 
+// Blocked gets blocked issues via the daemon
+func (c *Client) Blocked(args *BlockedArgs) (*Response, error) {
+	return c.Execute(OpBlocked, args)
+}
+
 // Stale gets stale issues via the daemon
 func (c *Client) Stale(args *StaleArgs) (*Response, error) {
 	return c.Execute(OpStale, args)

internal/rpc/protocol.go

@@ -20,6 +20,7 @@ const (
 	OpCount           = "count"
 	OpShow            = "show"
 	OpReady           = "ready"
+	OpBlocked         = "blocked"
 	OpStale           = "stale"
 	OpStats           = "stats"
 	OpDepAdd          = "dep_add"
@@ -253,6 +254,12 @@ type ReadyArgs struct {
 	SortPolicy string   `json:"sort_policy,omitempty"`
 	Labels     []string `json:"labels,omitempty"`
 	LabelsAny  []string `json:"labels_any,omitempty"`
+	ParentID   string   `json:"parent_id,omitempty"` // Filter to descendants of this bead/epic
+}
+
+// BlockedArgs represents arguments for the blocked operation
+type BlockedArgs struct {
+	ParentID string `json:"parent_id,omitempty"` // Filter to descendants of this bead/epic
 }
 
 // StaleArgs represents arguments for the stale command

internal/rpc/server_issues_epics.go

@@ -1262,6 +1262,7 @@ func (s *Server) handleReady(req *Request) Response {
 
 	wf := types.WorkFilter{
 		Status:     types.StatusOpen,
+		Type:       readyArgs.Type,
 		Priority:   readyArgs.Priority,
 		Unassigned: readyArgs.Unassigned,
 		Limit:      readyArgs.Limit,
@@ -1272,6 +1273,9 @@ func (s *Server) handleReady(req *Request) Response {
 	if readyArgs.Assignee != "" && !readyArgs.Unassigned {
 		wf.Assignee = &readyArgs.Assignee
 	}
+	if readyArgs.ParentID != "" {
+		wf.ParentID = &readyArgs.ParentID
+	}
 
 	ctx := s.reqCtx(req)
 	issues, err := store.GetReadyWork(ctx, wf)
@@ -1289,6 +1293,44 @@ func (s *Server) handleReady(req *Request) Response {
 	}
 }
 
+func (s *Server) handleBlocked(req *Request) Response {
+	var blockedArgs BlockedArgs
+	if err := json.Unmarshal(req.Args, &blockedArgs); err != nil {
+		return Response{
+			Success: false,
+			Error:   fmt.Sprintf("invalid blocked args: %v", err),
+		}
+	}
+
+	store := s.storage
+	if store == nil {
+		return Response{
+			Success: false,
+			Error:   "storage not available (global daemon deprecated - use local daemon instead with 'bd daemon' in your project)",
+		}
+	}
+
+	var wf types.WorkFilter
+	if blockedArgs.ParentID != "" {
+		wf.ParentID = &blockedArgs.ParentID
+	}
+
+	ctx := s.reqCtx(req)
+	blocked, err := store.GetBlockedIssues(ctx, wf)
+	if err != nil {
+		return Response{
+			Success: false,
+			Error:   fmt.Sprintf("failed to get blocked issues: %v", err),
+		}
+	}
+
+	data, _ := json.Marshal(blocked)
+	return Response{
+		Success: true,
+		Data:    data,
+	}
+}
+
 func (s *Server) handleStale(req *Request) Response {
 	var staleArgs StaleArgs
 	if err := json.Unmarshal(req.Args, &staleArgs); err != nil {

internal/rpc/server_routing_validation_diagnostics.go

@@ -188,6 +188,8 @@ func (s *Server) handleRequest(req *Request) Response {
 		resp = s.handleResolveID(req)
 	case OpReady:
 		resp = s.handleReady(req)
+	case OpBlocked:
+		resp = s.handleBlocked(req)
 	case OpStale:
 		resp = s.handleStale(req)
 	case OpStats: