refactor(runtime): make language runtime policy-agnostic; drop VQA viz

Set up the runtime so a second language-conditioned policy reuses the
CLI/REPL/UI instead of copying pi052's. The tick loop, REPL, panel, and
interactive CLI are now policy-independent in lerobot/runtime/; a policy
plugs in only a LanguageConditionedPolicyAdapter.

- Move repl.py, ui.py, and runtime_cli.py (-> cli.py) from
  pi052/inference/ into lerobot/runtime/. Generalize labels/titles
  (panel_label param, [runtime] prefixes).
- lerobot.runtime.cli.run(argv, *, adapter_factory, panel_label, prog)
  is the shared entry; policy loading already dispatches generically via
  the factory on cfg.type.
- lerobot-pi052-runtime is now a thin entry (scripts/lerobot_pi052_runtime.py)
  that passes PI052PolicyAdapter into run(). pi052/inference/ keeps only
  the adapter.
- Drop PI052Runtime back-compat wrapper (no consumers).
- Drop VQA visualization: delete inference/vqa.py + test_pi052_vqa_loc.py,
  remove answer_vqa/VQAResult from the Protocol + adapter, and the
  /question command + overlay paths from the CLI/REPL.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

tests/runtime/test_language_runtime.py

@@ -1,7 +1,6 @@
 from lerobot.runtime import (
     LanguageConditionedRuntime,
     RuntimeState,
-    VQAResult,
 )
 
 
@@ -19,9 +18,6 @@ class FakeAdapter:
         self.text_calls.append((kind, user_text))
         return "new plan"
 
-    def answer_vqa(self, question, camera, observation, state):
-        return VQAResult(answer=f"answer: {question}")
-
     def update_language_state(self, observation, state):
         self.updated = True
         state.set_context("subtask", "pick cup", label="subtask")