feat(prism): add tweak gradiant visualisors (#655)

[plastikfan]

Summary by CodeRabbit

• New Features

  • Added several new terminal visualizations: waveform, sweep, bloom, and bands.
  • Introduced a visualizer registry so available renderers can be listed and registered consistently.

• Bug Fixes

  • Rendering now safely returns an empty result when there is no color data or the display width is invalid.

• Tests

  • Added coverage for visualizer output, naming, registry behavior, and empty-input cases.

[coderabbitai]

Caution

Review failed

The pull request is closed.

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: 2b3caabb-8ea1-4418-bb1a-8950527b3e0c

📥 Commits

Reviewing files that changed from the base of the PR and between e7f2dff and 13eed9f.

📒 Files selected for processing (12)

• src/prism/workshop/bands.go
• src/prism/workshop/bands_test.go
• src/prism/workshop/bloom.go
• src/prism/workshop/bloom_test.go
• src/prism/workshop/helpers_test.go
• src/prism/workshop/sweep.go
• src/prism/workshop/sweep_test.go
• src/prism/workshop/visualiser.go
• src/prism/workshop/visualiser_test.go
• src/prism/workshop/waveform.go
• src/prism/workshop/waveform_test.go
• src/prism/workshop/workshop-suite_test.go

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📝 Walkthrough

Walkthrough

Adds a new workshop package implementing a GradientVisualiser interface with a package-level registry (Register, Visualisers, Reset, RegisterVisualisers). Four concrete visualisers—Waveform, Sweep, Bloom, Bands—render gradient-colored terminal output using curve/easing transforms, each with accompanying Ginkgo/Gomega tests and shared test helpers.

Changes

Prism Workshop Visualisers

Layer / File(s)	Summary
Visualiser interface and registry src/prism/workshop/visualiser.go, visualiser_test.go	Defines GradientVisualiser interface (Render, Name), a package-level registry with Register, Visualisers, Reset, and RegisterVisualisers that registers the four concrete visualisers; tested with a spy renderer and registry lifecycle assertions.
Waveform visualiser waveform.go, waveform_test.go	WaveformVisualiser renders a sine-wave height row and a gradient sweep bar row, using stepForPosition, animationSpeed, and writeColouredChar; validated via table-driven tests.
Sweep visualiser sweep.go, sweep_test.go	SweepVisualiser renders a scrolling block bar cycling colors via (col + animFrame) % len(steps); validated via table-driven tests.
Bloom visualiser bloom.go, bloom_test.go	BloomVisualiser renders a pulsing diamond of rings using maxRings, ringAt, charForRing, and pulseFactor; validated via table-driven tests.
Bands visualiser bands.go, bands_test.go	BandsVisualiser renders a braille curve row and a gradient bar row using brailleForHeight, easedCurve, applyCurve, applyEasing; validated via table-driven tests.
Shared test helpers and suite entrypoint helpers_test.go, workshop-suite_test.go	Adds makeSteps, stepsEntry, containsAny helpers and TestWorkshop Ginkgo suite entrypoint used across visualiser tests.

Estimated code review effort: 3 (Moderate) | ~30 minutes

Sequence Diagram(s)

sequenceDiagram
  participant Bootstrap
  participant Registry
  participant Visualiser
  participant Renderer

  Bootstrap->>Registry: RegisterVisualisers()
  Registry->>Visualiser: Register(instances)
  Bootstrap->>Registry: Visualisers()
  Registry-->>Bootstrap: []GradientVisualiser
  loop for each visualiser
    Bootstrap->>Visualiser: Render(steps, curve, easing, animFrame)
    Visualiser->>Renderer: applyCurve/applyEasing/pulseFactor transforms
    Renderer-->>Visualiser: styled colored string
    Visualiser-->>Bootstrap: rendered output
  end

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Possibly related issues

• tweak gradient model extension #653: Introduces visualisers consuming curve/easing gradient concepts matching this PR's implementation.
• create tweak GradientVisualiser #655: Implements the same GradientVisualiser registry and concrete visualiser set, including BandsVisualiser, described in the issue.

✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch feat/tweak-gradient-visualisors

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