Closes #15072

Summary

Fix Anthropic model normalization so Hermes only converts dots to hyphens for Claude model IDs.

Before this change, Anthropic wire normalization rewrote any dotted model ID, which broke Anthropic-compatible custom endpoints serving non-Claude models such as:

• qwen3.6-35B
• qwen3.5-plus
• MiniMax-M2.7

That produced requests like qwen3-6-35B, which the upstream endpoint rejected as model_not_found.

Root cause

agent.anthropic_adapter.normalize_model_name() applied this rule globally:

• strip anthropic/
• replace . with -

That is correct for Claude IDs like claude-sonnet-4.6 -> claude-sonnet-4-6, but incorrect for non-Claude IDs on Anthropic-compatible APIs.

Fix

Change Anthropic normalization to:

• keep stripping anthropic/
• only replace . with - when the bare model ID starts with claude-
• keep dotted non-Claude IDs unchanged by default

Examples after this patch:

• anthropic/claude-sonnet-4.6 -> claude-sonnet-4-6
• qwen3.6-35B -> qwen3.6-35B
• anthropic/qwen3.6-35B -> qwen3.6-35B
• MiniMax-M2.7 -> MiniMax-M2.7

Tests

Added/updated regression coverage for:

• Qwen-style dotted model IDs staying intact on the Anthropic path
• existing Claude dot-to-hyphen behavior remaining unchanged
• MiniMax normalization expectation aligned with the new non-Claude behavior

Validation

Passed locally:

• pytest -o addopts='' tests/agent/test_anthropic_adapter.py
• pytest -o addopts='' tests/agent/test_minimax_provider.py -k 'normalize_'

I did not run the full test_minimax_provider.py file in this environment because it imports run_agent and the local env is missing the fire dependency, which is unrelated to this fix.