Add route declarations and automatic port allocation to MCP agent

Service definitions can now declare routes per component instead of
manual port mappings:

  [[components.routes]]
  name = "rest"
  port = 8443
  mode = "l4"

The agent allocates free host ports at deploy time and injects
$PORT/$PORT_<NAME> env vars into containers. Backward compatible:
components with old-style ports= work unchanged.

Changes:
- Proto: RouteSpec message, routes + env fields on ComponentSpec
- Servicedef: RouteDef parsing and validation from TOML
- Registry: component_routes table with host_port tracking
- Runtime: Env field on ContainerSpec, -e flag in BuildRunArgs
- Agent: PortAllocator (random 10000-60000, availability check),
  deploy wiring for route→port mapping and env injection

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

internal/servicedef/servicedef.go

@@ -21,16 +21,27 @@ type ServiceDef struct {
 	Components []ComponentDef `toml:"components"`
 }
 
+// RouteDef describes a route for a component, used for automatic port
+// allocation and mc-proxy integration.
+type RouteDef struct {
+	Name     string `toml:"name,omitempty"`
+	Port     int    `toml:"port"`
+	Mode     string `toml:"mode,omitempty"`
+	Hostname string `toml:"hostname,omitempty"`
+}
+
 // ComponentDef describes a single container component within a service.
 type ComponentDef struct {
-	Name    string   `toml:"name"`
-	Image   string   `toml:"image"`
-	Network string   `toml:"network,omitempty"`
-	User    string   `toml:"user,omitempty"`
-	Restart string   `toml:"restart,omitempty"`
-	Ports   []string `toml:"ports,omitempty"`
-	Volumes []string `toml:"volumes,omitempty"`
-	Cmd     []string `toml:"cmd,omitempty"`
+	Name    string     `toml:"name"`
+	Image   string     `toml:"image"`
+	Network string     `toml:"network,omitempty"`
+	User    string     `toml:"user,omitempty"`
+	Restart string     `toml:"restart,omitempty"`
+	Ports   []string   `toml:"ports,omitempty"`
+	Volumes []string   `toml:"volumes,omitempty"`
+	Cmd     []string   `toml:"cmd,omitempty"`
+	Routes  []RouteDef `toml:"routes,omitempty"`
+	Env     []string   `toml:"env,omitempty"`
 }
 
 // Load reads and parses a TOML service definition file. If the active field
@@ -129,11 +140,46 @@ func validate(def *ServiceDef) error {
 			return fmt.Errorf("duplicate component name %q in service %q", c.Name, def.Name)
 		}
 		seen[c.Name] = true
+
+		if err := validateRoutes(c.Name, def.Name, c.Routes); err != nil {
+			return err
+		}
 	}
 
 	return nil
 }
 
+// validateRoutes checks that routes within a component are valid.
+func validateRoutes(compName, svcName string, routes []RouteDef) error {
+	if len(routes) == 0 {
+		return nil
+	}
+
+	routeNames := make(map[string]bool)
+	for i, r := range routes {
+		if r.Port <= 0 {
+			return fmt.Errorf("route port must be > 0 in component %q of service %q", compName, svcName)
+		}
+		if r.Mode != "" && r.Mode != "l4" && r.Mode != "l7" {
+			return fmt.Errorf("route mode must be \"l4\" or \"l7\" in component %q of service %q", compName, svcName)
+		}
+		if len(routes) > 1 && r.Name == "" {
+			return fmt.Errorf("route name is required when component has multiple routes in component %q of service %q", compName, svcName)
+		}
+
+		// Use index-based key for unnamed single routes.
+		key := r.Name
+		if key == "" {
+			key = fmt.Sprintf("_route_%d", i)
+		}
+		if routeNames[key] {
+			return fmt.Errorf("duplicate route name %q in component %q of service %q", r.Name, compName, svcName)
+		}
+		routeNames[key] = true
+	}
+	return nil
+}
+
 // ToProto converts a ServiceDef to a proto ServiceSpec.
 func ToProto(def *ServiceDef) *mcpv1.ServiceSpec {
 	spec := &mcpv1.ServiceSpec{
@@ -142,7 +188,7 @@ func ToProto(def *ServiceDef) *mcpv1.ServiceSpec {
 	}
 
 	for _, c := range def.Components {
-		spec.Components = append(spec.Components, &mcpv1.ComponentSpec{
+		cs := &mcpv1.ComponentSpec{
 			Name:    c.Name,
 			Image:   c.Image,
 			Network: c.Network,
@@ -151,7 +197,17 @@ func ToProto(def *ServiceDef) *mcpv1.ServiceSpec {
 			Ports:   c.Ports,
 			Volumes: c.Volumes,
 			Cmd:     c.Cmd,
-		})
+			Env:     c.Env,
+		}
+		for _, r := range c.Routes {
+			cs.Routes = append(cs.Routes, &mcpv1.RouteSpec{
+				Name:     r.Name,
+				Port:     int32(r.Port),
+				Mode:     r.Mode,
+				Hostname: r.Hostname,
+			})
+		}
+		spec.Components = append(spec.Components, cs)
 	}
 
 	return spec
@@ -169,7 +225,7 @@ func FromProto(spec *mcpv1.ServiceSpec, node string) *ServiceDef {
 	}
 
 	for _, c := range spec.GetComponents() {
-		def.Components = append(def.Components, ComponentDef{
+		cd := ComponentDef{
 			Name:    c.GetName(),
 			Image:   c.GetImage(),
 			Network: c.GetNetwork(),
@@ -178,7 +234,17 @@ func FromProto(spec *mcpv1.ServiceSpec, node string) *ServiceDef {
 			Ports:   c.GetPorts(),
 			Volumes: c.GetVolumes(),
 			Cmd:     c.GetCmd(),
-		})
+			Env:     c.GetEnv(),
+		}
+		for _, r := range c.GetRoutes() {
+			cd.Routes = append(cd.Routes, RouteDef{
+				Name:     r.GetName(),
+				Port:     int(r.GetPort()),
+				Mode:     r.GetMode(),
+				Hostname: r.GetHostname(),
+			})
+		}
+		def.Components = append(def.Components, cd)
 	}
 
 	return def