fix(anthropic): live model fetching + adaptive thinking for 4.5+ models

- Add _fetch_anthropic_models() to hermes_cli/models.py — hits the
  Anthropic /v1/models endpoint to get the live model catalog. Handles
  both API key and OAuth token auth headers.

- Wire it into provider_model_ids() so both 'hermes model' and
  'hermes setup model' show the live list instead of a stale static one.

- Update static _PROVIDER_MODELS fallback with full current catalog:
  opus-4-6, sonnet-4-6, opus-4-5, sonnet-4-5, opus-4, sonnet-4, haiku-4-5

- Update model_metadata.py with context lengths for all current models.

- Fix thinking parameter for 4.5+ models: use type='adaptive' instead
  of type='enabled' (Anthropic deprecated 'enabled' for newer models,
  warns at runtime). Detects model version from the model name string.

Verified live:
  hermes model → Anthropic → auto-detected creds → shows 7 live models
  hermes chat --provider anthropic --model claude-opus-4-6 → works

hermes_cli/setup.py

@@ -1229,9 +1229,12 @@ def setup_model_provider(config: dict):
                     _set_default_model(config, custom)
             # else: keep current
         elif selected_provider == "anthropic":
-            anthropic_models = [
-                "claude-sonnet-4-20250514",
-                "claude-opus-4-20250514",
+            # Try live model list first, fall back to static
+            from hermes_cli.models import provider_model_ids
+            live_models = provider_model_ids("anthropic")
+            anthropic_models = live_models if live_models else [
+                "claude-opus-4-6",
+                "claude-sonnet-4-6",
                 "claude-haiku-4-5-20251001",
             ]
             model_choices = list(anthropic_models)