feat: braille oscilloscope / VU meter widget (TUI-014)

[chernistry]

Summary

• Adds BrailleCanvas class that maps a 2D dot-space onto Unicode braille characters (U+2800..U+28FF) at 2x4 subpixel resolution per terminal cell, with Bresenham line drawing
• Adds OscilloscopeWidget (Textual Static) that renders agent activity as scrolling waveforms with per-channel colors, grid overlay, and peak hold tracking
• Graceful fallbacks: sparkline block chars for non-braille terminals, ASCII bars for no_unicode accessibility, static single-row bars for no_animations mode
• 23 unit tests covering canvas primitives, channel lifecycle, peak decay, color determinism, max-channel cap, and all fallback paths

Test plan

• uv run pytest tests/unit/test_oscilloscope.py -x -q -- 23 passed
• uv run ruff check src/bernstein/tui/oscilloscope.py tests/unit/test_oscilloscope.py -- clean
• Pre-push typecheck -- 0 errors
• Visual integration into app.py deferred to future WU

🤖 Generated with Claude Code

[kilo-code-bot]

Code Review Summary

Status: No Issues Found | Recommendation: Merge

Files Reviewed (2 files)

• src/bernstein/tui/oscilloscope.py - Implements BrailleCanvas and OscilloscopeWidget with support for braille waveforms, fallbacks, and accessibility modes
• tests/unit/test_oscilloscope.py - 23 comprehensive unit tests covering all components

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_{Reviewed by grok-code-fast-1 · 86,840 tokens}

[github-actions]

CI Summary

Check	Result
Repo hygiene	✅ success
Lint	✅ success
Type check	✅ success
Tests	❌ failure
Spelling	✅ success
Dead code	✅ success
Workflow lint	✅ success
Dist size	✅ success
SonarCloud	⏭️ skipped

Coverage and detailed reports are available via Codecov and the Checks tab.

[github-actions]

AI Review (GitHub Models)

Summary

The pull request adds a new feature, a braille oscilloscope and VU meter widget, to the Bernstein CLI orchestrator. This enhancement aims to improve accessibility for visually impaired users by providing an alternative data visualization method through braille representation.

Risk Assessment

Medium: While the feature appears beneficial for accessibility, introducing new UI components can introduce bugs and significantly affect user experience if not thoroughly tested. Additionally, ensuring that the new widget adheres to existing design patterns and API stability is crucial.

Actionable Recommendations

• Conduct thorough testing of the new widget across different terminal emulators to ensure proper rendering.
• Update the documentation to include instructions for users on how to utilize the new braille widget.
• Ensure the widget has adequate error handling for edge cases (e.g., missing data).
• Review performance implications of the new rendering logic to ensure it doesn't introduce latency.
• Incorporate feedback from users with disabilities to optimize usability

[sonarqubecloud]

Quality Gate failed

Failed conditions
C Reliability Rating on New Code (required ≥ A)

See analysis details on SonarQube Cloud

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