fix(openclaw): remove MCP/Skills/Prompts support from OpenClaw

OpenClaw only needs provider management functionality, not MCP, Skills,
or Prompts features. This commit removes the incorrectly added support:

- Revert SCHEMA_VERSION from 6 to 5 (remove v5->v6 migration)
- Remove enabled_openclaw field from mcp_servers and skills tables
- Remove openclaw field from McpApps and SkillApps structs
- Update DAO queries to exclude enabled_openclaw column
- Fix frontend components and types to exclude openclaw from MCP/Prompts
- Update all related test files

src-tauri/src/deeplink/mcp.rs

@@ -167,7 +167,6 @@ pub(crate) fn parse_mcp_apps(apps_str: &str) -> Result<McpApps, AppError> {
         codex: false,
         gemini: false,
         opencode: false,
-        openclaw: false,
     };
 
     for app in apps_str.split(',') {
@@ -176,7 +175,10 @@ pub(crate) fn parse_mcp_apps(apps_str: &str) -> Result<McpApps, AppError> {
             "codex" => apps.codex = true,
             "gemini" => apps.gemini = true,
             "opencode" => apps.opencode = true,
-            "openclaw" => apps.openclaw = true,
+            "openclaw" => {
+                // OpenClaw doesn't support MCP, ignore silently
+                log::debug!("OpenClaw doesn't support MCP, ignoring in apps parameter");
+            }
             other => {
                 return Err(AppError::InvalidInput(format!(
                     "Invalid app in 'apps': {other}"