fix(server): remove deprecated mock-only check in /pipelines/start

transport builder 가 이미 env + config 기반으로 mock/http 결정하므로
서버 레이어의 mock==false 거부는 불필요. 제거.

sister-agent/.claude/sessions/.last_inbox_check

@@ -1 +1 @@
-1775808589
+1775809049

sister-agent/.claude/state/test-recommendation.json

@@ -1,5 +1,5 @@
 {
-  "timestamp": "2026-04-10T08:10:32Z",
+  "timestamp": "2026-04-10T08:17:29Z",
   "changed_file": "/home/erang/hanarang-rails/src/server/http.ts",
   "test_command": "npm test",
   "related_test": "",

sister-agent/.claude/state/tool-failure-counter.txt

@@ -0,0 +1 @@
+1 1775808904

src/server/http.ts

@@ -79,17 +79,10 @@ export async function startHttpServer(opts: ServerOpts): Promise<{
             issues: parsed.error.issues,
           });
         }
-        const { project, requirements, mock: useMock } = parsed.data;
-
-        // Only mock mode is wired right now — real transports come in a follow-up.
-        if (!useMock) {
-          return sendJson(res, 501, {
-            error: "not_implemented",
-            message: "Non-mock transport wiring deferred to next iteration.",
-          });
-        }
+        const { project, requirements } = parsed.data;
 
         // Run pipeline (async, but we await for this simple demo)
+        // Transport is determined by env RAILS_TRANSPORT_MODE and rails.config.yaml
         const result = await runPipeline({
           projectName: project,
           requirements,