fix(autoobserve): register the AutoObserve routes with the OpenAPI coverage guard

The OpenAPI coverage guard from main panics on a router function it does
not know and pins the set of enabled MCP tools. The enterprise AutoObserve
routes mount under /api, so autoobserve_routes joins ROUTER_PREFIXES, and
their seven operations, MCP tools by design, are listed as enterprise tools.

src/api/http/src/handler/http/router/openapi_coverage/mcp_enabled.txt

@@ -6,6 +6,13 @@ ent ActivateRemoteTaskSigningCandidate
 all AddPanel
 oss AddUserToOrg
 all AssumeServiceAccount
+ent AutoObserveCoverage
+ent AutoObserveCoverageHistory
+ent AutoObserveDeleteMark
+ent AutoObserveEntityTypes
+ent AutoObserveListMarks
+ent AutoObservePutMark
+ent AutoObserveSuggestions
 all CancelAlertMute
 ent CancelAnomalyTraining
 all CancelDowntime

src/api/http/src/handler/http/router/openapi_coverage/mod.rs

@@ -59,6 +59,7 @@ const ROUTER_PREFIXES: &[(&str, &str)] = &[
     ("public_dashboard_admin_routes", "/api"),
     ("ai_chat_routes", "/api"),
     ("alert_calibration_routes", "/api"),
+    ("autoobserve_routes", "/api"),
     ("downtime_routes", "/api"),
     ("report_routes", "/api"),
     ("oncall_routes", "/api"),