docs: add runtime profiling evidence path

[div0rce]

Summary

Adds a runtime profiling evidence path and keeps the runtime profile analyzer compatible with existing CI. This change is software-only and does not add new hardware evidence.

Changes

• Clarified runtime profile docs so committed CSVs are treated as bounded historical samples, not broad runtime proof.
• Updated scripts/analyze_runtime_profile.py to support both one-file CI mode and combined RTOS/cooperative summary mode.
• Regenerated artifacts/runtime/runtime_summary.json from the committed CSV samples and added no_data handling for empty templates.

Validation Tasks

• git status --short --branch
• git diff --check
• platformio test -e native
• scripts/check_app_core_includes.sh
• ESP-IDF RTOS backend build
• ESP-IDF cooperative backend build
• Runtime profile analyzer single-file mode
• Runtime profile analyzer combined mode
• Claim-safety grep contains only explicit non-claim boundary wording