Update MCP service definition to convention-driven format

Drop uses_mcdsl, explicit image URL, network, restart. Use
service-level version, route declarations, and derived defaults
per PLATFORM_EVOLUTION.md conventions.

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

ARCHITECTURE.md

@@ -247,27 +247,23 @@ and routes `docs.metacircular.net` to mcdoc's listener.
 ```toml
 name = "mcdoc"
 node = "rift"
-active = true
-path = "mcdoc"
-
-[build]
-uses_mcdsl = false
+version = "v0.1.0"
 
 [build.images]
 mcdoc = "Dockerfile"
 
 [[components]]
 name = "mcdoc"
-image = "mcr.svc.mcp.metacircular.net:8443/mcdoc:v0.1.0"
-network = "mcpnet"
-restart = "unless-stopped"
-volumes = ["/srv/mcdoc:/srv/mcdoc"]
-cmd = ["server", "--config", "/srv/mcdoc/mcdoc.toml"]
+
+[[components.routes]]
+port = 443
+mode = "l7"
+hostname = "docs.metacircular.net"
 ```
 
 Port assignment is pending MCP support for automatic port allocation
-and mc-proxy route registration. Until then, a manually assigned port
-will be used.
+and mc-proxy route registration (see `PLATFORM_EVOLUTION.md`). Until
+then, a manually assigned port will be used.
 
 ### mc-proxy Routes