Add Smithery support: smithery.yaml, PORT env var, Dockerfile update

- Add smithery.yaml for container-based HTTP publishing on Smithery
- Support PORT environment variable as fallback in config defaults
- Update Dockerfile to use PORT instead of SENTINEL_GATE_SERVER_HTTP_ADDR

Author: Sentinel-Gate

Dockerfile

@@ -60,7 +60,8 @@ COPY --from=perms /data /data
 VOLUME ["/data"]
 ENV SENTINEL_GATE_STATE_PATH=/data/state.json
 # Bind to all interfaces inside container (default is localhost-only for security).
-ENV SENTINEL_GATE_SERVER_HTTP_ADDR=":8080"
+# Cloud platforms (Smithery, Cloud Run) override PORT at runtime.
+ENV PORT=8080
 
 # Run as non-root user
 USER nonroot:nonroot

internal/config/config.go

@@ -19,6 +19,7 @@
 // For Pro features, see the sentinel-gate-pro module.
 package config
 
+import "os"
 
 // OSSConfig is the top-level configuration for Sentinel Gate OSS.
 // It contains only the essential fields for a minimalist MCP proxy.
@@ -278,8 +279,13 @@ type AuditFileConfig struct {
 func (c *OSSConfig) SetDefaults() {
 	// Server defaults — bind to localhost only for security.
 	// Users who need network access must explicitly set http_addr: ":8080" or "0.0.0.0:8080".
+	// Cloud platforms (Smithery, Cloud Run, etc.) set PORT to indicate the listening port.
 	if c.Server.HTTPAddr == "" {
-		c.Server.HTTPAddr = "127.0.0.1:8080"
+		if port := os.Getenv("PORT"); port != "" {
+			c.Server.HTTPAddr = ":" + port
+		} else {
+			c.Server.HTTPAddr = "127.0.0.1:8080"
+		}
 	}
 	if c.Server.LogLevel == "" {
 		c.Server.LogLevel = "info"

smithery.yaml

@@ -0,0 +1,12 @@
+# Smithery configuration for SentinelGate
+# https://smithery.ai/docs/build/project-config/smithery-yaml
+runtime: "container"
+build:
+  dockerfile: "Dockerfile"
+  dockerBuildPath: "."
+startCommand:
+  type: "http"
+  configSchema:
+    type: "object"
+    properties: {}
+    required: []