[Spec Decode] Remove Medusa and MLP speculator support (#61701)

Signed-off-by: Woosuk Kwon <woosuk@inferact.ai>
Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>

.github/mergify.yml

@@ -494,8 +494,7 @@ pull_request_rules:
       - files~=^tests/v1/e2e/spec_decode/
       - files~=^examples/features/speculative_decoding/
       - files~=^vllm/model_executor/models/.*eagle.*\.py
-      - files=vllm/model_executor/models/mlp_speculator.py
-      - files~=^vllm/transformers_utils/configs/(eagle|medusa|mlp_speculator)\.py
+      - files~=^vllm/transformers_utils/configs/eagle\.py
   actions:
     label:
       add:

.github/workflows/issue_autolabel.yml

@@ -279,7 +279,6 @@ jobs:
               "speculative-decoding": {
                 keywords: [
                   { term: "eagle",  searchIn: "title" },
-                  { term: "medusa", searchIn: "title" },
                 ],
                 substrings: [
                   { term: "speculative decoding", searchIn: "title" },