Enforce FR modification notices and fix Bedrock optional dependency handling

[manas-fortifyroot]

Summary

Adds a repo-local FR modification notice workflow for upstream-derived files and fixes Bedrock instrumentation so SDK initialization does not hard-crash when boto3 is installed but anthropic is absent.

Changes

• Added scripts/apply-fr-modification-notices.py with apply/check modes.
• Added notice normalization coverage for modified upstream .py and .toml files.
• Added CI enforcement in .github/workflows/fr-pr.yaml.
• Standardized FR modification notices across upstream-derived modified files.
• Skips FR-added files from notice insertion.
• Made Bedrock anthropic handling lazy/guarded.
• Added regression coverage for Bedrock optional dependency behavior.
• Rebranded stale user-facing Traceloop guidance in fork runtime code.

Validation

• python3 scripts/test-apply-fr-modification-notices.py
• python3 scripts/apply-fr-modification-notices.py --check --base-ref fr-v0.52.6.x
• Bedrock optional dependency targeted tests.
• fr-openllmetry-py/scripts/run-tests.sh --all

Notes

This fork should be merged first, then a new fork tag should be cut. The FR SDK should be re-vendored from that final tag before merging the SDK PR.