fix(mcp): preserve user's enabled:false and apply disabled_mcps to all MCP sources

Commit 598a4389 refactored config-handler into separate modules but
dropped the disabledMcps parameter from loadMcpConfigs() and did not
handle the spread-order overwrite where .mcp.json MCPs (hardcoded
enabled:true) overwrote user's enabled:false from opencode.json.

Changes:
- Re-add disabledMcps parameter to loadMcpConfigs() in loader.ts
- Capture user's enabled:false MCPs before merge, restore after
- Pass disabled_mcps to loadMcpConfigs for .mcp.json filtering
- Delete disabled_mcps entries from final merged result
- Add 8 new tests covering both fixes

src/plugin-handlers/mcp-config-handler.ts

@@ -3,19 +3,58 @@ import { loadMcpConfigs } from "../features/claude-code-mcp-loader";
 import { createBuiltinMcps } from "../mcp";
 import type { PluginComponents } from "./plugin-components-loader";
 
+type McpEntry = Record<string, unknown>;
+
+function captureUserDisabledMcps(
+  userMcp: Record<string, unknown> | undefined
+): Set<string> {
+  const disabled = new Set<string>();
+  if (!userMcp) return disabled;
+
+  for (const [name, value] of Object.entries(userMcp)) {
+    if (
+      value &&
+      typeof value === "object" &&
+      "enabled" in value &&
+      (value as McpEntry).enabled === false
+    ) {
+      disabled.add(name);
+    }
+  }
+
+  return disabled;
+}
+
 export async function applyMcpConfig(params: {
   config: Record<string, unknown>;
   pluginConfig: OhMyOpenCodeConfig;
   pluginComponents: PluginComponents;
 }): Promise<void> {
+  const disabledMcps = params.pluginConfig.disabled_mcps ?? [];
+  const userMcp = params.config.mcp as Record<string, unknown> | undefined;
+  const userDisabledMcps = captureUserDisabledMcps(userMcp);
+
   const mcpResult = params.pluginConfig.claude_code?.mcp ?? true
-    ? await loadMcpConfigs()
+    ? await loadMcpConfigs(disabledMcps)
     : { servers: {} };
 
-  params.config.mcp = {
-    ...createBuiltinMcps(params.pluginConfig.disabled_mcps, params.pluginConfig),
-    ...(params.config.mcp as Record<string, unknown>),
+  const merged = {
+    ...createBuiltinMcps(disabledMcps, params.pluginConfig),
+    ...(userMcp ?? {}),
     ...mcpResult.servers,
     ...params.pluginComponents.mcpServers,
-  };
+  } as Record<string, McpEntry>;
+
+  for (const name of userDisabledMcps) {
+    if (merged[name]) {
+      merged[name] = { ...merged[name], enabled: false };
+    }
+  }
+
+  const disabledSet = new Set(disabledMcps);
+  for (const name of disabledSet) {
+    delete merged[name];
+  }
+
+  params.config.mcp = merged;
 }