fix(bedrock): enable Claude 1M context metadata

[alfredomtx]

Summary

• update Bedrock Claude context metadata for 1M-capable Opus/Sonnet models
• align get_bedrock_context_length() with versioned and inference-profile Claude IDs
• send additionalModelRequestFields.anthropic_beta=["context-1m-2025-08-07"] on the Bedrock Converse path when the selected Claude model advertises >200K context
• keep standard 200K Claude models from receiving the 1M beta

Why

Some Bedrock Claude routes require the 1M context beta field in the Converse request. Without it, Hermes can budget for a 1M context window but Bedrock still rejects prompts over 200K tokens.

This keeps metadata and request construction in sync.

Tests

• python -m pytest tests/agent/test_bedrock_1m_context.py tests/agent/test_bedrock_adapter.py -q

Result: 130 passed

Review

• Independent review flagged the missing Converse additionalModelRequestFields path; this PR now includes that fix and regression coverage.
• AU inference-profile IDs are covered so 1M metadata and beta injection work for regional profile prefixes, not just us/global/eu.

[alt-glitch]

Duplicate of #31309 — same fix (forward context-1m beta on the Bedrock Converse adapter via additionalModelRequestFields, #31277). #31309 is the earlier open PR.