Add Hub and Kernel protocol reference docs

Introduces new documentation for Hub and Kernel protocols, including schema references for composer, license, marketplace, space, tenant, context, logger, manifest, plugin, router, and scoped-storage. Also standardizes meta.json titles to singular form across AI, API, automation, data, driver, permission, and system references. Removes obsolete license test file and updates build-docs script.

Author: hotlong

content/docs/references/ai/agent/meta.json

@@ -1,3 +1,3 @@
 {
-  "title": "Agents"
+  "title": "Agent"
 }

content/docs/references/ai/conversation/meta.json

@@ -1,3 +1,3 @@
 {
-  "title": "Conversations"
+  "title": "Conversation"
 }

content/docs/references/ai/cost/meta.json

@@ -1,3 +1,3 @@
 {
-  "title": "Cost Management"
+  "title": "Cost"
 }

content/docs/references/ai/nlq/meta.json

@@ -1,3 +1,3 @@
 {
-  "title": "Natural Language Query"
+  "title": "Nlq"
 }

content/docs/references/ai/predictive/meta.json

@@ -1,3 +1,3 @@
 {
-  "title": "Predictive Models"
+  "title": "Predictive"
 }

content/docs/references/ai/rag-pipeline/meta.json

@@ -1,3 +1,3 @@
 {
-  "title": "RAG Pipelines"
+  "title": "Rag Pipeline"
 }

content/docs/references/api/contract/meta.json

@@ -1,3 +1,3 @@
 {
-  "title": "API Contracts"
+  "title": "Contract"
 }

content/docs/references/api/discovery/meta.json

@@ -1,3 +1,3 @@
 {
-  "title": "Service Discovery"
+  "title": "Discovery"
 }

content/docs/references/api/realtime/meta.json

@@ -1,3 +1,3 @@
 {
-  "title": "Real-time Communication"
+  "title": "Realtime"
 }

content/docs/references/automation/flow/meta.json

@@ -1,3 +1,3 @@
 {
-  "title": "Flows"
+  "title": "Flow"
 }