Add local debugger console clearing

[bjdodson-openai]

Description

Adds frontend-only console clearing without disrupting the active stream or other debugger state.

• Clears rendered entries and deduplication keys locally.
• Preserves target identity, stream ownership, prompt history, and Performance state.
• Adds focused regression coverage for state isolation.

Type of Change

• Bug fix (non-breaking change that fixes an issue)
• Documentation improvement
• Performance optimization
• Test improvement
• Other (new debugger capability)

Testing

• Tests pass locally (bazel test //...)
• Added/updated tests for changes (if applicable)
• Tested on multiple platforms (iOS/Android/Web/macOS as applicable)
• Manual testing performed (describe below)

Testing Details

• Incremental branch: Focused Console 5/5, complete panel 27/27, and full CLI 349/349 passed; production build, lint, syntax, formatting, diff, and query checks passed.
• Assembled debugger stack: npm test passed 436/436; the CLI production build passed.
• Focused //src/valdi_modules/src/valdi/web_renderer:test passed.
• bazel query //... passed.
• The broad Valdi suite reproduced the established 12 unrelated failures; all new debugger specs passed.

Checklist

• Code follows project style guidelines
• Documentation updated (if needed)
• No breaking changes (or documented in description)
• Commit messages follow conventional format
• No secrets, API keys, or internal URLs included

Related Issues

Relates to #154

Additional Context

Stack 16/22. Stacked on #168 (bjd/debugger-web-performance). Review this PR as the single incremental commit cbb42be9 against that base; do not merge it before its parent.

[github-actions]

📊 PR Size: size/M

Total changes: 101 lines (4 files)

Top files changed:

• npm_modules/cli/src/debugger/devtoolsPanel.spec.ts: +73 -1
• npm_modules/cli/debugger/devtools-panel.html: +13 -0
• npm_modules/cli/debugger/devtools-panel.js: +9 -3
• npm_modules/cli/debugger/devtools-panel.css: +1 -1

_{Size calculated as additions + deletions. Labels: XS (<10), S (<50), M (<250), L (<1000), XL (1000+)}