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/runtime/podman.go

@@ -49,6 +49,9 @@ func (p *Podman) BuildRunArgs(spec ContainerSpec) []string {
 	for _, vol := range spec.Volumes {
 		args = append(args, "-v", vol)
 	}
+	for _, env := range spec.Env {
+		args = append(args, "-e", env)
+	}
 
 	args = append(args, spec.Image)
 	args = append(args, spec.Cmd...)