fix(api-proxy): mention COPILOT_API_KEY in OpenCode unconfigured error messages

Agent-Logs-Url: https://github.com/github/gh-aw-firewall/sessions/c897ec94-027b-4ce5-8d61-e9c34d171ed9

Co-authored-by: lpcox <15877973+lpcox@users.noreply.github.com>

Author: Copilot

containers/api-proxy/providers/opencode.js

@@ -185,7 +185,7 @@ function createOpenCodeAdapter(env, { candidateAdapters = [] } = {}) {
           statusCode: 503,
           body: {
             error: {
-              message: 'OpenCode proxy (port 10004) is not enabled. Set AWF_ENABLE_OPENCODE=true and configure at least one of OPENAI_API_KEY, ANTHROPIC_API_KEY, or COPILOT_GITHUB_TOKEN.',
+              message: 'OpenCode proxy (port 10004) is not enabled. Set AWF_ENABLE_OPENCODE=true and configure at least one of OPENAI_API_KEY, ANTHROPIC_API_KEY, COPILOT_GITHUB_TOKEN, or COPILOT_API_KEY.',
               type: 'provider_not_configured',
               provider: 'opencode',
               port: 10004,
@@ -197,7 +197,7 @@ function createOpenCodeAdapter(env, { candidateAdapters = [] } = {}) {
         statusCode: 503,
         body: {
           error: {
-            message: 'Credentials for OpenCode (port 10004) are not configured. Set at least one of OPENAI_API_KEY, ANTHROPIC_API_KEY, or COPILOT_GITHUB_TOKEN.',
+            message: 'Credentials for OpenCode (port 10004) are not configured. Set at least one of OPENAI_API_KEY, ANTHROPIC_API_KEY, COPILOT_GITHUB_TOKEN, or COPILOT_API_KEY.',
             type: 'provider_not_configured',
             provider: 'opencode',
             port: 10004,

containers/api-proxy/server.test.js

@@ -2515,6 +2515,13 @@ describe('provider adapter alwaysBind', () => {
     expect(statusCode).toBe(503);
     expect(body.error.type).toBe('provider_not_configured');
     expect(body.error.message).toMatch(/OPENAI_API_KEY/);
+    expect(body.error.message).toMatch(/COPILOT_API_KEY/);
+  });
+
+  it('opencode getUnconfiguredResponse mentions COPILOT_API_KEY when not enabled', () => {
+    const adapter = createOpenCodeAdapter({});
+    const { body } = adapter.getUnconfiguredResponse();
+    expect(body.error.message).toMatch(/COPILOT_API_KEY/);
   });
 
   it('opencode getUnconfiguredHealthResponse returns 503 with not_configured status (disabled)', () => {