perf(ci): drop dead uvicorn start from perf job

Since #915 the perf job gates only on test_frame_budget.py, which drives
the CSIProcessor pipeline in-process and makes no HTTP calls. The
"Start application" step (uvicorn + `sleep 10`) was therefore dead weight:
it existed only for the now-excluded api_throughput/inference_speed tests,
wasted ~10-15 s per main-push run, and dumped ~50 misleading
"router requires hardware setup" ERROR lines into every CI log for a
server no test touched. MOCK_POSE_DATA is server-only, unused here.

Removed the step and the vestigial env. The gated test is unchanged and
passes (verified locally, 3/3).

Co-Authored-By: claude-flow <ruv@ruv.net>

.github/workflows/ci.yml

@@ -267,20 +267,15 @@ jobs:
         pip install -r requirements.txt
         pip install pytest   # the perf suite is pytest, not locust
 
-    - name: Start application
-      working-directory: archive/v1
-      env:
-        # No CSI hardware in CI — serve mock pose data so the pose endpoints
-        # respond 200 under load instead of erroring "requires real CSI data".
-        MOCK_POSE_DATA: "true"
-      run: |
-        uvicorn src.api.main:app --host 0.0.0.0 --port 8000 &
-        sleep 10
+    # No "Start application" step: the gated test (test_frame_budget.py) drives
+    # the CSIProcessor pipeline in-process and makes no HTTP calls, so the old
+    # uvicorn server + `sleep 10` were dead weight — they only existed for the
+    # now-excluded api_throughput/inference_speed tests, and on every run dumped
+    # ~50 misleading "router requires hardware setup" ERROR lines for a server
+    # no test touched. MOCK_POSE_DATA is server-only and unused here.
 
     - name: Run performance tests
       working-directory: archive/v1
-      env:
-        MOCK_POSE_DATA: "true"
       run: |
         # Gate only on the genuine, deterministic perf guard:
         # test_frame_budget.py times the *real* CSIProcessor pipeline against