Fix web MCP DNS and crawler runtime

platform/mcp/compose.yaml

@@ -21,6 +21,12 @@ services:
       dockerfile: mcp/Dockerfile.web
     image: mike-ai/mcp-web:local
     container_name: mike-ai-mcp-web
+    # The relay fetches and validates public result pages itself.  It therefore
+    # needs both the private tool network and the explicitly separated egress
+    # network; keeping it on `tools` only makes search discovery work while
+    # every page fetch fails.
+    networks: [tools, egress]
+    dns: ["${AI_DNS:-1.1.1.1}"]
     environment:
       TINYSEARCH_MCP_URL: http://tinysearch:8000/mcp
       SEARXNG_URL: http://searxng:8080
@@ -33,6 +39,7 @@ services:
     <<: *tool-common
     image: searxng/searxng@sha256:e45d5894bfaa0bf8773b9f283795ae57f1c15ddb29c8cecb70b3665b0ce9ec60
     container_name: mike-ai-tools-searxng
+    dns: ["${AI_DNS:-1.1.1.1}"]
     volumes:
       - ${SEARXNG_SETTINGS_FILE:-../web-search/searxng-settings.example.yml}:/etc/searxng/settings.yml:ro
     networks: [tools, egress]
@@ -41,6 +48,13 @@ services:
     <<: *tool-common
     image: marcellm01/tinysearch@sha256:5a03d5a1f1b0fabe48f2a26e05db4a84bcb611106a57ec51e42db4549976aa9c
     container_name: mike-ai-tools-tinysearch
+    dns: ["${AI_DNS:-1.1.1.1}"]
+    # Crawl4AI keeps transient browser/session state here.  The container stays
+    # read-only; only this disposable runtime directory (and /tmp from the
+    # common hardening block) is writable.
+    tmpfs:
+      - /tmp:rw,noexec,nosuid,nodev,size=64m
+      - /home/tinysearch/.crawl4ai:rw,nosuid,nodev,size=256m,mode=1777
     shm_size: 1gb
     volumes:
       - tinysearch-models:/data/models