[CI] Fix and wire encoder/manager cudagraph unit tests (#49339)

Signed-off-by: Nick Hill <nickhill123@gmail.com>
Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

.buildkite/test_areas/cuda.yaml

@@ -26,7 +26,10 @@ steps:
   - vllm/v1/cudagraph_dispatcher.py
   - vllm/config/compilation.py
   - vllm/compilation
+  - vllm/v1/worker/encoder_cudagraph.py
+  - vllm/v1/worker/encoder_cudagraph_defs.py
   commands:
     - pytest -v -s v1/cudagraph/test_cudagraph_dispatch.py
     - pytest -v -s v1/cudagraph/test_cudagraph_mode.py
     - pytest -v -s v1/cudagraph/test_breakable_cudagraph.py
+    - pytest -v -s v1/cudagraph/test_encoder_cudagraph.py

.buildkite/test_areas/misc.yaml

@@ -143,6 +143,7 @@ steps:
     - pytest -v -s -m 'cpu_test' v1/core
     - pytest -v -s v1/structured_output
     - pytest -v -s v1/test_serial_utils.py
+    - pytest -v -s v1/cudagraph/test_cudagraph_manager.py
     - pytest -v -s -m 'cpu_test' v1/kv_connector/unit
     - pytest -v -s -m 'cpu_test' v1/metrics
 

tests/v1/cudagraph/test_encoder_cudagraph.py

@@ -108,6 +108,11 @@ def _make_manager_with_budgets(budgets: list[int]) -> EncoderCudaGraphManager:
     mgr.token_budgets = sorted(budgets)
     mgr.max_batch_size = 16
     mgr.use_dp = False
+    mgr.config = EncoderCudaGraphConfig(
+        modalities=["image"],
+        buffer_keys=[],
+        out_hidden_size=32,
+    )
     mgr.budget_graphs = {"default": {}}
     mgr.graph_pool = None
     mgr.graph_hits = 0