Add preferences service for cross-platform user settings storage

[myieye]

Summary

This PR introduces a new IPreferencesService that provides a unified interface for storing user preferences across platforms. When running in MAUI, it uses native MAUI Preferences; otherwise, it falls back to localStorage.

Key Changes

Backend (.NET)

• Added IPreferencesService interface with Get(), Set(), and Remove() methods
• Implemented PreferencesServiceJsInvokable wrapper around MAUI's IPreferences with JSInvokable attributes for JavaScript interop
• Registered the service in the MAUI dependency injection container
• Updated FwLiteProvider to expose the service to JavaScript

Frontend (TypeScript/Svelte)

• Generated TypeScript types for IPreferencesService interface
• Added tryUsePreferencesService() hook to safely access the preferences service
• Updated LexboxServiceRegistry to include the new service

Project Storage

• Refactored ProjectStorage to use the preferences service backend
• Created LocalStorageBackend class implementing IPreferencesService as a fallback
• Changed StorageProp.set() from synchronous to async to support both MAUI and localStorage backends
• Updated TasksView.svelte to properly await async storage operations

Implementation Details

• The preferences service is optional on the frontend (tryUsePreferencesService() returns undefined if unavailable)
• LocalStorageBackend wraps localStorage in an async interface for consistency
• Storage operations are now async-first, allowing callers to await or fire-and-forget
• Initial storage values load asynchronously; reactive state updates when ready
• Project-scoped keys use the format project:{projectCode}:{key} for isolation

https://claude.ai/code/session_01XdJtubGvpeSyetSuA3zfFA

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📝 Walkthrough

Walkthrough

This PR introduces a new IPreferencesService interface and its MAUI implementation to expose device preferences to JavaScript code via JSInterop. The service is registered in the DI container, exposed through TypeScript type definitions, integrated into the frontend service provider, and utilized in the project storage layer with localStorage fallback support.

Changes

Cohort / File(s)	Summary
Backend Service Definition backend/FwLite/FwLiteShared/Services/IPreferencesService.cs	New interface defining Get, Set, and Remove methods for key-value preferences accessible to JavaScript.
MAUI Service Implementation & DI backend/FwLite/FwLiteMaui/Services/PreferencesServiceJsInvokable.cs, backend/FwLite/FwLiteMaui/FwLiteMauiKernel.cs	JSInvokable wrapper class implementing IPreferencesService delegating to MAUI IPreferences, registered as singleton in DI.
Shared Service Provider backend/FwLite/FwLiteShared/Services/FwLiteProvider.cs	Added PreferencesService enum value and service resolution mapping to IPreferencesService interface.
Frontend Type Generation frontend/viewer/src/lib/dotnet-types/generated-types/FwLiteShared/Services/DotnetService.ts, frontend/viewer/src/lib/dotnet-types/generated-types/FwLiteShared/Services/IPreferencesService.ts, frontend/viewer/src/lib/dotnet-types/generated-types/FwLiteShared/Services/index.ts	Generated TypeScript definitions for DotnetService enum and IPreferencesService interface with Promise-based methods.
Frontend Service Provider Integration frontend/viewer/src/lib/services/service-provider.ts	Added PreferencesService type mapping and tryUsePreferencesService() helper function for safe service access.
Storage Refactoring frontend/viewer/src/lib/utils/project-storage.svelte.ts	Implemented LocalStorageBackend fallback, refactored StorageProp and ProjectStorage to accept backend parameter, converted storage operations to async, and integrated preferences service selection.
UI Component Update frontend/viewer/src/project/tasks/TasksView.svelte	Changed Select.Root binding from two-way bind:value to one-way value with explicit onValueChange handler.

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~20 minutes

Possibly related PRs

• #2142: Directly modifies the same project-storage.svelte.ts file, adding MAUI-aware preferences and async storage APIs.

Suggested labels

🟨Medium

Suggested reviewers

• hahn-kev
• imnasnainaec

Poem

🐰 A preferences service hops into view,
MAUI meets JavaScript, both old and new,
LocalStorage stands as a faithful friend,
While async pathways gracefully bend,
From storage pens come cleaner designs,
A rabbit celebrates—the code shines! ✨

🚥 Pre-merge checks | ✅ 2 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 7.69% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (2 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly and concisely summarizes the main change: introducing a preferences service for cross-platform user settings storage, which is the central feature of this PR.
Description check	✅ Passed	The description comprehensively explains the PR's purpose, key changes across backend and frontend, implementation details, and architectural decisions—all directly related to the changeset.

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✨ Finishing touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Post copyable unit tests in a comment
• Commit unit tests in branch claude/maui-preferences-storage-HWSj7

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[github-actions]

UI unit Tests

  1 files  ±0   50 suites  ±0   24s ⏱️ ±0s
138 tests ±0  138 ✅ ±0  0 💤 ±0  0 ❌ ±0 
203 runs  ±0  203 ✅ ±0  0 💤 ±0  0 ❌ ±0 

Results for commit 16ae6c9. ± Comparison against base commit 7995859.

♻️ This comment has been updated with latest results.

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Build	Status	Details	Updated (UTC)
default (Inspect)	✅ No changes detected	-	Feb 11, 2026, 2:37 PM

[github-actions]

C# Unit Tests

160 tests  ±0   160 ✅ ±0   19s ⏱️ -1s
 23 suites ±0     0 💤 ±0 
  1 files   ±0     0 ❌ ±0 

Results for commit 16ae6c9. ± Comparison against base commit 7995859.

♻️ This comment has been updated with latest results.

[coderabbitai]

Actionable comments posted: 1

🤖 Fix all issues with AI agents

In `@frontend/viewer/src/lib/utils/project-storage.svelte.ts`:
- Around line 56-84: Constructor calls load() fire-and-forget which can race
with set() and allow load() to overwrite `#value` with stale backend data; fix by
adding a simple sequencing guard: introduce a private sequence counter (e.g.
`#writeSeq` or `#initSeq`) on the class, increment it at the start of set(), and in
load() capture the current sequence before awaiting the backend and only assign
this.#value if the captured sequence still equals the current sequence; update
references to constructor, load(), set(), and `#value` accordingly so late load()
results no longer overwrite newer writes.