refactor(runtime): template-method adapter base + policy registry; rename CLI

Make the policy adapter architecturally clean and set up a single general
entry point for any language-conditioned policy.

Adapter architecture (Template Method):
- New lerobot/runtime/adapter.py: BaseLanguageAdapter owns the generic
  control loop (throttle → generate → gibberish/empty reject → subtask→memory
  cascade → diagnostics) and plan_from_text/handle_interjection. A policy
  supplies only select_action + generate_text + build_messages. The
  subtask→memory cascade is an overridable hook (_regenerate_context).
- GenerationConfig (typed, constructor-time) replaces config smuggled through
  RuntimeState.extra (temperature/top_p/min_new_tokens/chunks_per_regen).
- LanguageDiagnostics (typed, keyed by kind) replaces ~8 loose state.extra
  counter keys; the panel reads it via the adapter.
- looks_like_gibberish + split_plan_and_say move to runtime (generic).

Contract:
- LanguageConditionedPolicyAdapter protocol now states the true contract
  (select_action, update_language_state, handle_interjection); the runtime
  drops both getattr fallbacks.
- PI052PolicyAdapter shrinks to just its primitives (132 → ~half).

General entry point:
- lerobot/runtime/registry.py maps policy type → adapter (lazy import).
- run() resolves the adapter from the registry by policy type and defaults
  the panel label to it, so one CLI serves every policy.
- Rename lerobot-pi052-runtime → lerobot-language-runtime (general script);
  a new policy just registers its adapter, no new script.

Tests: new tests/runtime/test_adapter.py covers throttle/reject/cascade/
interjection; adapter + runtime + CLI-smoke tests updated for the new shape.

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

tests/runtime/test_language_runtime.py

@@ -7,21 +7,21 @@ from lerobot.runtime import (
 class FakeAdapter:
     def __init__(self):
         self.updated = False
-        self.text_calls = []
+        self.interjections = []
 
     def select_action(self, observation, state):
         assert observation == {"observation.state": 1}
         assert state.task == "clean"
         return ["a0", "a1"]
 
-    def select_text(self, kind, observation, state, user_text=None):
-        self.text_calls.append((kind, user_text))
-        return "new plan"
-
     def update_language_state(self, observation, state):
         self.updated = True
         state.set_context("subtask", "pick cup", label="subtask")
 
+    def handle_interjection(self, user_text, observation, state):
+        self.interjections.append(user_text)
+        state.set_context("plan", "new plan", label="plan")
+
 
 def test_runtime_tick_updates_language_enqueues_and_dispatches_action():
     adapter = FakeAdapter()
@@ -54,7 +54,7 @@ def test_runtime_handles_user_interjection():
 
     runtime.step_once()
 
-    assert ("interjection", "please say ok") in adapter.text_calls
+    assert "please say ok" in adapter.interjections
     assert runtime.state.language_context["plan"] == "new plan"