docs: API documentation and JSON schema updates

backend/internal/graph/schema.graphql

@@ -2,6 +2,12 @@ type Query {
   # Returns REQUIRE_SETUP if config is missing.
   systemStatus: SystemStatus!
 
+  # Fetch current configuration (admin only).
+  config: AppConfig!
+
+  # List directories on the server for UI pickers.
+  serverDirectories(path: String): [ServerDirectory!]!
+
   # Fetch a document by its slug path.
   document(slug: String!): Document
 
@@ -36,6 +42,15 @@ type Mutation {
 
   # Delete a document.
   deleteDocument(slug: String!): Boolean!
+
+  # Modify LDAP Configuration (admin only).
+  updateLdapConfig(input: LDAPInput): Boolean!
+
+  # Modify Storage Path (admin only).
+  updateStoragePath(path: String!): Boolean!
+
+  # Change the current user's password.
+  changePassword(old: String!, new: String!): Boolean!
 }
 
 # ── Types ──────────────────────────────────────────────────────────────────────
@@ -45,6 +60,23 @@ enum SystemStatus {
   REQUIRE_SETUP
 }
 
+type AppConfig {
+  storagePath: String!
+  ldap:        LDAPConfig
+}
+
+type LDAPConfig {
+  host:   String!
+  port:   Int!
+  baseDN: String!
+  bindDN: String!
+}
+
+type ServerDirectory {
+  name:   String!
+  path:   String!
+}
+
 type Document {
   slug:    String!
   content: String!