feat: initial SynapBus project scaffolding

Bootstrap the SynapBus project — a local-first, MCP-native agent-to-agent
messaging service written in Go.

Includes:
- Project constitution (10 architectural principles)
- 10 feature specs with implementation tasks:
  001 Core Messaging, 002 Agent Registry, 003 Human Auth (OAuth 2.1),
  004 Channels, 005 Web UI, 006 MCP Server, 007 Trace Logging,
  008 Semantic Search, 009 Attachments, 010 Swarm Patterns
- Go project scaffold (cobra CLI, SQLite schema, Makefile)
- Speckit templates and commands

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

cmd/synapbus/main.go

@@ -0,0 +1,52 @@
+package main
+
+import (
+	"fmt"
+	"os"
+
+	"github.com/spf13/cobra"
+)
+
+var (
+	port    int
+	dataDir string
+)
+
+func main() {
+	rootCmd := &cobra.Command{
+		Use:   "synapbus",
+		Short: "SynapBus — MCP-native agent-to-agent messaging",
+		Long:  "Local-first, MCP-native messaging service for AI agents. Single binary with embedded storage, semantic search, and a Slack-like Web UI.",
+	}
+
+	serveCmd := &cobra.Command{
+		Use:   "serve",
+		Short: "Start the SynapBus server",
+		RunE:  runServe,
+	}
+
+	serveCmd.Flags().IntVar(&port, "port", 8080, "HTTP server port")
+	serveCmd.Flags().StringVar(&dataDir, "data", "./data", "Data directory for storage")
+
+	rootCmd.AddCommand(serveCmd)
+
+	if err := rootCmd.Execute(); err != nil {
+		fmt.Fprintf(os.Stderr, "Error: %v\n", err)
+		os.Exit(1)
+	}
+}
+
+func runServe(cmd *cobra.Command, args []string) error {
+	// Check for environment variable overrides
+	if p := os.Getenv("SYNAPBUS_PORT"); p != "" {
+		fmt.Sscanf(p, "%d", &port)
+	}
+	if d := os.Getenv("SYNAPBUS_DATA_DIR"); d != "" {
+		dataDir = d
+	}
+
+	fmt.Printf("SynapBus starting on port %d with data dir %s\n", port, dataDir)
+	fmt.Println("TODO: Initialize storage, MCP server, REST API, and Web UI")
+
+	return nil
+}