fix(runtime): use XML-valid entity in flamegraph SVG (#32716)
- Replace ` ` with ` ` in the CPU flamegraph SVG template
- ` ` is an HTML entity not recognized by XML parsers, causing `XML
Parsing Error: undefined entity` when opening the SVG standalone
Fixes #32708
Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>