Add modular/optional feature packs and on-demand component installer for Video & Audio

[spelech]

Introduces modular, separately installable feature packs for Video Generation (video-generation) and Audio TTS (audio-tts).

Key changes:

• Updated Inno Setup installer.iss with [Components] (core, ext_video, ext_audio) and [Types] (full, compact, custom).
• Added --with-video and --with-audio opt-in flags to install.ps1 and install_linux.sh.
• Refactored setup_ai_tools.ps1 into discrete tasks Install-VideoPack and Install-AudioPack.
• Implemented IComponentManagerService & ComponentManagerService to query, install, and uninstall optional feature packs.
• Added REST endpoints GET /api/components, POST /api/components/install (with SSE progress stream), and POST /api/components/uninstall.
• Created FeaturePackBannerControl UI banner control and integrated missing pack banners into EngineStudioTabControl.
• Added "Installed Components & Add-ons" section with disk usage status and toggles in SettingsTabControl.
• Added unit & integration tests in ComponentManagerAndEndpointsTests.cs.

Fixes #15

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PR created automatically by Jules for task 454266730511521674 started by @spelech

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[spelech]

PR #22 Code Review: Modular Feature Packs & On-Demand Component Installer (Issue #15)

Verdict: APPROVED_WITH_NITPICKS 🟢 (with actionable recommendations)

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🌟 Key Strengths & Architectural Highlights

1. Clean Modular Architecture: Clean separation between core server functionality and optional feature packs (video-generation, audio-tts) across installer scripts, backend services, and front-end UI.
2. REST & SSE Endpoints: Clear REST API contract with endpoints /api/components, /api/components/install, and /api/components/uninstall supporting real-time Server-Sent Events (SSE) progress reporting.
3. Graceful UI Fallbacks: Reusable FeaturePackBannerControl in EngineStudioTabControl with rich metadata (Description, Disk Size, Min VRAM requirements) and single-click installation when components are missing.
4. Settings Management UI: Dedicated "Installed Components & Add-ons" section in SettingsTabControl with real-time status pills and toggle/uninstall actions.
5. Cross-Platform Script Support: Multi-platform installer support across Inno Setup ([Components] & [Types]), PowerShell (-WithVideo, -WithAudio), Linux shell script (--with-video, --with-audio), and setup_ai_tools.ps1.
6. Automated Testing: Integration test suite in ComponentManagerAndEndpointsTests.cs covering querying, installation, and uninstallation.

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🔍 Findings & Recommended Improvements

1. Path Resolution: Avoid Directory.GetCurrentDirectory() in Service/Desktop Execution [High Priority]

Location: Services/ComponentManagerService.cs

• IsVideoPackInstalled, IsAudioPackInstalled, InstallComponentAsync, and UninstallComponentAsync use Directory.GetCurrentDirectory().
• When running as a Windows Service (or launched from system directories/shortcuts), Directory.GetCurrentDirectory() points to C:\Windows\System32 (or / on Linux), which can cause directory creation/deletion in the wrong path or trigger UnauthorizedAccessException.
• Recommendation: Use AppContext.BaseDirectory or resolve against configured settings (settings.WorkflowsPath, etc.):

var baseDir = AppContext.BaseDirectory;
var videoWorkflowDir = Path.Combine(baseDir, "Workflows", "Video");

2. Inno Setup: Map Components to [Dirs] [Medium Priority]

Location: scripts/installer.iss

• installer.iss defines [Types] and [Components] (core, ext_video, ext_audio), but there are no [Dirs] or [Files] entries associated with Components: ext_video or Components: ext_audio.
• Choosing "Full" vs "Compact" in the Inno Setup wizard currently does not create the corresponding feature pack folder scaffolding.
• Recommendation: Add a [Dirs] section linking the component flags:

[Dirs]
Name: "{app}\Workflows\Video"; Components: ext_video
Name: "{app}\kokoro-fastapi"; Components: ext_audio
Name: "{app}\models\audio"; Components: ext_audio

3. Concurrency: Fire-and-forget Task.Run in SSE Stream Handler [Medium Priority]

Location: Endpoints/ComponentEndpoints.cs

• In app.MapPost("/api/components/install"), Progress<double> triggers _ = Task.Run(async () => ...). Because these background tasks are un-awaited, the endpoint method can complete, execute Results.Empty, and close the HTTP response stream while un-awaited tasks are still queued on syncLock, potentially causing ObjectDisposedException.
• Recommendation: Synchronize SSE writes sequentially or buffer progress via a System.Threading.Channels.Channel<T> consumed by a streaming writer.

4. Bash Argument Parsing Loop in install_linux.sh [Low Priority]

Location: scripts/install_linux.sh

• Calling shift inside a for arg in "$@" loop can cause skipped arguments because the for loop already iterates over the pre-expanded positional arguments.
• Recommendation: Use a standard while [ $# -gt 0 ] loop:

while [ $# -gt 0 ]; do
  case "$1" in
    --with-video)
      WITH_VIDEO=1
      shift
      ;;
    --with-audio)
      WITH_AUDIO=1
      shift
      ;;
    *)
      shift
      ;;
  esac
done

5. HttpClient Lifetime & Initial State Loading in SettingsViewModel.cs [Low Priority]

Location: LocalLLMServerManager.Shared/ViewModels/SettingsViewModel.cs

• RefreshComponentStatusesAsync and ToggleComponentAsync create unmanaged new HttpClient() instances. Wrap with using var http = new HttpClient(); or use a shared client.
• Call RefreshComponentStatusesAsync(apiBase, http) inside LoadSettingsAsync so the UI initializes with current component statuses immediately without requiring a manual refresh.

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🏁 Summary

Overall, this PR provides a solid foundation for modular feature packs and on-demand installer capabilities. The architecture is clean, cohesive, and integrates smoothly into the app UI and backend endpoints. Addressing the path resolution and Inno Setup [Dirs] mapping will ensure rock-solid behavior in production installations.

[spelech]

Integrated and merged into main as part of release v3.7.0.