feat(docs): collapse sidebar sections by default

Activates fumadocs' built-in collapse on every section. Only the
section containing the current page expands; others stay collapsed
until the user clicks them. Foundation for the typographic sidebar
pass in the next commit.

docs/content/docs/benchmarks/meta.json

@@ -0,0 +1,5 @@
+{
+  "title": "Benchmarks",
+  "defaultOpen": false,
+  "pages": ["link-detection"]
+}

docs/content/docs/cli-reference/meta.json

@@ -0,0 +1,16 @@
+{
+  "title": "CLI Reference",
+  "defaultOpen": false,
+  "pages": [
+    "ktx-setup",
+    "ktx-connection",
+    "ktx-scan",
+    "ktx-ingest",
+    "ktx-sl",
+    "ktx-wiki",
+    "ktx-serve",
+    "ktx-status",
+    "ktx-agent",
+    "ktx-dev"
+  ]
+}

docs/content/docs/community/meta.json

@@ -0,0 +1,5 @@
+{
+  "title": "Community",
+  "defaultOpen": false,
+  "pages": ["contributing"]
+}

docs/content/docs/concepts/meta.json

@@ -0,0 +1,5 @@
+{
+  "title": "Concepts",
+  "defaultOpen": false,
+  "pages": ["the-context-layer", "context-as-code"]
+}

docs/content/docs/getting-started/meta.json

@@ -0,0 +1,5 @@
+{
+  "title": "Getting Started",
+  "defaultOpen": false,
+  "pages": ["introduction", "quickstart"]
+}

docs/content/docs/guides/meta.json

@@ -0,0 +1,5 @@
+{
+  "title": "Guides",
+  "defaultOpen": false,
+  "pages": ["building-context", "writing-context", "serving-agents"]
+}

docs/content/docs/integrations/meta.json

@@ -0,0 +1,5 @@
+{
+  "title": "Integrations",
+  "defaultOpen": false,
+  "pages": ["primary-sources", "context-sources", "agent-clients"]
+}