fix: resolve MiniMax 401 auth error by defaulting to anthropic_messages (#2103)

MiniMax's default base URL was /v1 which caused runtime_provider to
default to chat_completions mode (OpenAI-style Authorization: Bearer
header). MiniMax rejects this with a 401 because they require the
Anthropic-style x-api-key header.

Changes:
- auth.py: Change default inference_base_url for minimax and minimax-cn
  from /v1 to /anthropic
- runtime_provider.py: Auto-correct stale /v1 URLs from existing .env
  files to /anthropic, and always default minimax/minimax-cn providers
  to anthropic_messages mode
- Update tests to reflect new defaults, add tests for stale URL
  auto-correction and explicit api_mode override

Based on PR #2100 by @devorun. Fixes #2094.

Co-authored-by: Test <test@test.com>

hermes_cli/runtime_provider.py

@@ -387,6 +387,12 @@ def resolve_runtime_provider(
             # (e.g. https://api.minimax.io/anthropic, https://dashscope.../anthropic)
             elif base_url.rstrip("/").endswith("/anthropic"):
                 api_mode = "anthropic_messages"
+            # MiniMax providers always use Anthropic Messages API.
+            # Auto-correct stale /v1 URLs (from old .env or config) to /anthropic.
+            elif provider in ("minimax", "minimax-cn"):
+                api_mode = "anthropic_messages"
+                if base_url.rstrip("/").endswith("/v1"):
+                    base_url = base_url.rstrip("/")[:-3] + "/anthropic"
         return {
             "provider": provider,
             "api_mode": api_mode,