perf(rpc): use bd daemon protocol to reduce subprocess overhead

Replace bd subprocess calls in gt commands with daemon RPC when available.
Each subprocess call has ~40ms overhead for Go binary startup, so using
the daemon's Unix socket protocol significantly reduces latency.

Changes:
- Add RPC client to beads package (beads_rpc.go)
- Modify List/Show/Update/Close methods to try RPC first, fall back to subprocess
- Replace runBdPrime() with direct content output (avoids bd subprocess)
- Replace checkPendingEscalations() to use beads.List() with RPC
- Replace hook.go bd subprocess calls with beads package methods

The RPC client:
- Connects to daemon via Unix socket at .beads/bd.sock
- Uses JSON-based request/response protocol (same as bd daemon)
- Falls back gracefully to subprocess if daemon unavailable
- Lazy-initializes connection on first use

Performance improvement targets (from bd-2zd.2):
- gt prime < 100ms (was 5.8s with subprocess chain)
- gt hook < 100ms (was ~323ms)

Closes: bd-2zd.2

internal/beads/beads.go

@@ -119,6 +119,12 @@ type Beads struct {
 	// Populated on first call to getTownRoot() to avoid filesystem walk on every operation.
 	townRoot     string
 	searchedRoot bool
+
+	// RPC client for daemon communication (lazy-initialized).
+	// When available, RPC is preferred over subprocess for performance.
+	rpcClient     *rpcClient
+	rpcChecked    bool
+	rpcAvailable  bool
 }
 
 // New creates a new Beads wrapper for the given directory.
@@ -287,7 +293,14 @@ func filterBeadsEnv(environ []string) []string {
 }
 
 // List returns issues matching the given options.
+// Uses daemon RPC when available for better performance (~40ms faster).
 func (b *Beads) List(opts ListOptions) ([]*Issue, error) {
+	// Try RPC first (faster when daemon is running)
+	if issues, err := b.listViaRPC(opts); err == nil {
+		return issues, nil
+	}
+
+	// Fall back to subprocess
 	args := []string{"list", "--json"}
 
 	if opts.Status != "" {
@@ -400,7 +413,14 @@ func (b *Beads) ReadyWithType(issueType string) ([]*Issue, error) {
 }
 
 // Show returns detailed information about an issue.
+// Uses daemon RPC when available for better performance (~40ms faster).
 func (b *Beads) Show(id string) (*Issue, error) {
+	// Try RPC first (faster when daemon is running)
+	if issue, err := b.showViaRPC(id); err == nil {
+		return issue, nil
+	}
+
+	// Fall back to subprocess
 	out, err := b.run("show", id, "--json")
 	if err != nil {
 		return nil, err
@@ -559,7 +579,14 @@ func (b *Beads) CreateWithID(id string, opts CreateOptions) (*Issue, error) {
 }
 
 // Update updates an existing issue.
+// Uses daemon RPC when available for better performance (~40ms faster).
 func (b *Beads) Update(id string, opts UpdateOptions) error {
+	// Try RPC first (faster when daemon is running)
+	if err := b.updateViaRPC(id, opts); err == nil {
+		return nil
+	}
+
+	// Fall back to subprocess
 	args := []string{"update", id}
 
 	if opts.Title != nil {
@@ -598,15 +625,26 @@ func (b *Beads) Update(id string, opts UpdateOptions) error {
 // Close closes one or more issues.
 // If a runtime session ID is set in the environment, it is passed to bd close
 // for work attribution tracking (see decision 009-session-events-architecture.md).
+// Uses daemon RPC when available for better performance (~40ms faster per call).
 func (b *Beads) Close(ids ...string) error {
 	if len(ids) == 0 {
 		return nil
 	}
 
+	sessionID := runtime.SessionIDFromEnv()
+
+	// Try RPC for single-issue closes (faster when daemon is running)
+	if len(ids) == 1 {
+		if err := b.closeViaRPC(ids[0], "", sessionID, false); err == nil {
+			return nil
+		}
+	}
+
+	// Fall back to subprocess
 	args := append([]string{"close"}, ids...)
 
 	// Pass session ID for work attribution if available
-	if sessionID := runtime.SessionIDFromEnv(); sessionID != "" {
+	if sessionID != "" {
 		args = append(args, "--session="+sessionID)
 	}
 
@@ -617,16 +655,51 @@ func (b *Beads) Close(ids ...string) error {
 // CloseWithReason closes one or more issues with a reason.
 // If a runtime session ID is set in the environment, it is passed to bd close
 // for work attribution tracking (see decision 009-session-events-architecture.md).
+// Uses daemon RPC when available for better performance (~40ms faster per call).
 func (b *Beads) CloseWithReason(reason string, ids ...string) error {
 	if len(ids) == 0 {
 		return nil
 	}
 
+	sessionID := runtime.SessionIDFromEnv()
+
+	// Try RPC for single-issue closes (faster when daemon is running)
+	if len(ids) == 1 {
+		if err := b.closeViaRPC(ids[0], reason, sessionID, false); err == nil {
+			return nil
+		}
+	}
+
+	// Fall back to subprocess
 	args := append([]string{"close"}, ids...)
 	args = append(args, "--reason="+reason)
 
 	// Pass session ID for work attribution if available
-	if sessionID := runtime.SessionIDFromEnv(); sessionID != "" {
+	if sessionID != "" {
+		args = append(args, "--session="+sessionID)
+	}
+
+	_, err := b.run(args...)
+	return err
+}
+
+// CloseForced closes an issue with force flag and optional reason.
+// The force flag bypasses blockers and other validation checks.
+// Uses daemon RPC when available for better performance (~40ms faster).
+func (b *Beads) CloseForced(id, reason string) error {
+	sessionID := runtime.SessionIDFromEnv()
+
+	// Try RPC first (faster when daemon is running)
+	if err := b.closeViaRPC(id, reason, sessionID, true); err == nil {
+		return nil
+	}
+
+	// Fall back to subprocess
+	args := []string{"close", id, "--force"}
+	if reason != "" {
+		args = append(args, "--reason="+reason)
+	}
+	if sessionID != "" {
 		args = append(args, "--session="+sessionID)
 	}
 
@@ -800,3 +873,19 @@ func ProvisionPrimeMDForWorktree(worktreePath string) error {
 	// Provision PRIME.md in the target directory
 	return ProvisionPrimeMD(beadsDir)
 }
+
+// GetPrimeContent returns the beads workflow context content.
+// It checks for a custom PRIME.md file first, otherwise returns the default.
+// This eliminates the need to spawn a bd subprocess for gt prime.
+func GetPrimeContent(workDir string) string {
+	beadsDir := ResolveBeadsDir(workDir)
+	primePath := filepath.Join(beadsDir, "PRIME.md")
+
+	// Check for custom PRIME.md
+	if content, err := os.ReadFile(primePath); err == nil {
+		return strings.TrimSpace(string(content))
+	}
+
+	// Return default content
+	return strings.TrimSpace(primeContent)
+}