fix(bedrock): add auxiliary client support and dot preservation for model names

[yetisnowman]

Problem

The bedrock provider added in #7920 has two edge cases that cause errors:

1. Auxiliary client does not support bedrock — auxiliary_client.py resolve_provider_client() has no bedrock branch, so configuring auxiliary.provider: bedrock in config produces a warning and disables LLM-based context compression/summarization.

2. Model name dots get incorrectly replaced — _anthropic_preserve_dots() whitelist does not include bedrock. Bedrock model IDs contain dots (e.g. us.anthropic.claude-opus-4-6-v1) which normalize_model_name() converts to hyphens, producing invalid model identifiers and HTTP 400 errors.

Fix

• Add a bedrock branch to resolve_provider_client() that reuses build_anthropic_bedrock_client() with IAM auth
• Add bedrock to the _anthropic_preserve_dots() provider set
• Update docstring to document bedrock dot preservation

Testing

Verified on a live Hermes gateway instance running us.anthropic.claude-opus-4-6-v1 via Bedrock:

• No more HTTP 400 errors
• Auxiliary LLM warning resolved
• Slack + WeChat gateway stable

[teknium1]

Thanks for the detailed write-up and live validation — this is well-scoped and clearly motivated!

This is an automated hermes-sweeper review. Both changes proposed by this PR landed on main independently before this PR was reviewed:

• Dot-preservation fix (_anthropic_preserve_dots + bedrock-runtime. base-URL heuristic): merged via PR [Bug]: Bedrock inference profile model ID dots mangled to hyphens → HTTP 400 "invalid model identifier" #11976, commit 1cf1016e7 — run_agent.py line 7260 now includes "bedrock" in the allowlist and "bedrock-runtime." as a URL guard.
• Auxiliary client bedrock branch (aws_sdk branch in resolve_provider_client()): merged as commit 7dc6eb9fb — agent/auxiliary_client.py lines 2039–2069 implement the identical bedrock client construction via build_anthropic_bedrock_client().

Both fixes are reachable from the current main HEAD. Closing as implemented.