docs: drop the extensions guide from the sidebar (#659)

Signed-off-by: Casey Gowrie <ctgowrie@gmail.com>
Co-authored-by: Claude Opus 4.8 <noreply@anthropic.com>

.changeset/hide-extensions-nav.md

@@ -0,0 +1,5 @@
+---
+"eve": patch
+---
+
+Keep the mounted extensions guide out of the docs sidebar for now. The page stays at `/docs/extensions`, but the feature isn't surfaced in the nav while its API stabilizes.

docs/meta.json

@@ -12,7 +12,6 @@
     "sandbox",
     "subagents",
     "schedules",
-    "extensions",
     "evals",
     "---",
     "guides",

scripts/check-docs.mjs

@@ -37,6 +37,9 @@ const ROOTS = [
 const SIDEBAR_EXEMPT_PAGES = new Set([
   // Linked from the global footer instead of the docs sidebar.
   "responsible-use.md",
+  // Reachable at its URL but intentionally kept out of the sidebar for now
+  // while the mounted-extensions feature stabilizes.
+  "extensions.md",
 ]);
 
 // Only the top-level README.md is excluded. Nested READMEs (e.g.