fix: sanitize Bedrock tool errors

[jbg]

Summary

• remove Unicode Tags Block characters from Bedrock tool-error text before it re-enters model context
• preserve the complete ordinary error message and status
• add regressions for hidden tags and ordinary error text

This restores visible/model-input equivalence for the Bedrock ToolResponse error branch. It addresses the confirmed private audit finding project-loupe/audit-goose#651 without publishing exploit-specific content.

Validation

• Regression proof before the fix: hidden-tag test failed while ordinary-error preservation passed
• cargo fmt --check
• cargo test -p goose --features aws-providers --lib tool_response_error_ — 2 passed
• cargo test -p goose --features aws-providers --lib providers::formats::bedrock::tests — 39 passed
• cargo build -p goose --features aws-providers
• cargo clippy -p goose --features aws-providers --all-targets -- -D warnings
• git diff --check

Limitations

This changes only the Bedrock tool-error formatter. Other model/tool metadata ingress paths are tracked separately and are outside this PR.

This finding was discovered by Project Loupe.