fix(auxiliary): pass raw base_url to _maybe_wrap_anthropic for correct transport detection

[chengoak]

Summary

Fixes HTTP 404 errors when using Anthropic-compatible providers (Kimi Coding, MiniMax) for auxiliary tasks (title generation, etc.).

Root Cause

_to_openai_base_url() rewrites Anthropic-protocol URLs to OpenAI-compatible format:

• /anthropic → /v1
• /coding → /coding/v1

However, _maybe_wrap_anthropic() needs the original URL to correctly detect whether the endpoint speaks Anthropic Messages protocol via _endpoint_speaks_anthropic_messages().

Before this fix:

• MiniMax: /anthropic rewritten to /v1, then _endpoint_speaks_anthropic_messages(/v1) returned False → no Anthropic wrapping → 404 on /v1/chat/completions
• Kimi Coding: /coding rewritten to /coding/v1, but _endpoint_speaks_anthropic_messages still matched due to /coding in URL, causing double /v1 confusion

After this fix:

• OpenAI client uses the rewritten URL (correct for chat.completions)
• _maybe_wrap_anthropic uses the raw URL for transport detection (correct for protocol selection)

Changes

In agent/auxiliary_client.py, 4 locations now preserve raw_base_url:

1. _resolve_api_key_provider() — pool path
2. _resolve_api_key_provider() — API key path
3. resolve_provider_client() — named custom provider
4. resolve_provider_client() — API-key providers

Test Plan

• Verify title generation works with Kimi Coding provider
• Verify auxiliary calls work with MiniMax provider
• Ensure no regression for OpenAI-format providers

Related

Fixes the "⚠ Auxiliary title generation failed: HTTP 404" error reported when using api.kimi.com/coding or MiniMax as the auxiliary provider.

[alt-glitch]

Likely duplicate of #17361 and #17387 — same root cause: _to_openai_base_url() rewrites URL before _maybe_wrap_anthropic() can detect Anthropic protocol, causing 404 on MiniMax/Kimi auxiliary calls.

[chengoak]

Hi @teknium1, this PR complements #17451 (which skipped kimi-coding in vision auto-detect).

This fix addresses the root cause: was rewriting Anthropic URLs before could detect the transport protocol, causing 404s for both Kimi Coding and MiniMax auxiliary clients.

The fix preserves the raw base_url for transport detection while still using the rewritten URL for OpenAI client creation — a more general solution than per-provider special-casing.

Would appreciate a review when you have a moment. Thanks!

[alt-glitch]

Likely duplicate of #17361 and #17387 — same root cause.

[Austin5925]

Confirmed this fix is needed. Hit the same 404 on a fresh v0.11.0 install with MINIMAX_CN_BASE_URL=https://api.minimaxi.com/anthropic — every new session's title_generation throws Auxiliary title generation failed: HTTP 404: 404 page not found to the Telegram chat.

Verified locally with a hostname-whitelist hack on _to_openai_base_url (only skips the rewrite for api.minimaxi.com), but this PR's approach is the right architectural fix — passing the raw base_url through to _maybe_wrap_anthropic covers every Anthropic-protocol provider in one place instead of growing a host list. +1 to merge.