Add RPC infrastructure and updated database

- RPC Phase 1: Protocol, server, client implementation
- Updated renumber.go with proper text reference updates (3-phase approach)
- Clean database exported: 344 issues (bd-1 to bd-344)
- Added DAEMON_DESIGN.md documentation
- Updated go.mod/go.sum for RPC dependencies

Amp-Thread-ID: https://ampcode.com/threads/T-456af77c-8b7f-4004-9027-c37b95e10ea5
Co-authored-by: Amp <amp@ampcode.com>

internal/rpc/protocol.go

@@ -0,0 +1,88 @@
+package rpc
+
+import "encoding/json"
+
+// Request represents an RPC request from a client to the daemon.
+type Request struct {
+	Operation string          `json:"operation"`
+	Args      json.RawMessage `json:"args"`
+}
+
+// Response represents an RPC response from the daemon to a client.
+type Response struct {
+	Success bool            `json:"success"`
+	Data    json.RawMessage `json:"data,omitempty"`
+	Error   string          `json:"error,omitempty"`
+}
+
+// BatchRequest represents a batch of operations to execute atomically.
+type BatchRequest struct {
+	Operations []Request `json:"operations"`
+	Atomic     bool      `json:"atomic"`
+}
+
+// Operations supported by the daemon.
+const (
+	OpCreate       = "create"
+	OpUpdate       = "update"
+	OpClose        = "close"
+	OpList         = "list"
+	OpShow         = "show"
+	OpReady        = "ready"
+	OpBlocked      = "blocked"
+	OpStats        = "stats"
+	OpDepAdd       = "dep_add"
+	OpDepRemove    = "dep_remove"
+	OpDepTree      = "dep_tree"
+	OpLabelAdd     = "label_add"
+	OpLabelRemove  = "label_remove"
+	OpLabelList    = "label_list"
+	OpLabelListAll = "label_list_all"
+	OpExport       = "export"
+	OpImport       = "import"
+	OpCompact      = "compact"
+	OpRestore      = "restore"
+	OpBatch        = "batch"
+)
+
+// NewRequest creates a new RPC request with the given operation and arguments.
+func NewRequest(operation string, args interface{}) (*Request, error) {
+	argsJSON, err := json.Marshal(args)
+	if err != nil {
+		return nil, err
+	}
+	return &Request{
+		Operation: operation,
+		Args:      argsJSON,
+	}, nil
+}
+
+// NewSuccessResponse creates a successful response with the given data.
+func NewSuccessResponse(data interface{}) (*Response, error) {
+	dataJSON, err := json.Marshal(data)
+	if err != nil {
+		return nil, err
+	}
+	return &Response{
+		Success: true,
+		Data:    dataJSON,
+	}, nil
+}
+
+// NewErrorResponse creates an error response with the given error message.
+func NewErrorResponse(err error) *Response {
+	return &Response{
+		Success: false,
+		Error:   err.Error(),
+	}
+}
+
+// UnmarshalArgs unmarshals the request arguments into the given value.
+func (r *Request) UnmarshalArgs(v interface{}) error {
+	return json.Unmarshal(r.Args, v)
+}
+
+// UnmarshalData unmarshals the response data into the given value.
+func (r *Response) UnmarshalData(v interface{}) error {
+	return json.Unmarshal(r.Data, v)
+}