[ShiftHackZ]

Description

Fixes #613.

Connection setup and startup now continue when optional hypernetwork discovery fails, including a 404 from servers without that endpoint. Required metadata failures, cancellation, timeouts and nonrecoverable errors still propagate.

The H-Net dialog fetches again on every opening and uses cached entries when discovery fails. Recovery belongs to the domain use cases; the repository exposes strict fetch/get operations. Removes the combined repository method and unused no-op preloader, and updates the affected KDoc.

Checklist

• I have ensured this PR does not contain any breaking changes for existing functionality
• I have added automated tests that cover the new behavior and removed obsolete tests and code
• I have added documentation for any new public APIs and update existing documentation for any changes to public APIs

Tested On

• Android: Emulator
• Android: Real device
• iOS: Simulator
• iOS: Real iPhone device

Validation:

• 55 targeted unit tests pass, covering preload recovery, required failures, refresh/cache fallback, retries, cancellation, deadlines and fatal errors.
• Kotlin lint, Android compilation/debug APK assembly and shared iOS Simulator compilation pass. iOS runtime was not exercised.
• Pixel 3a XL / Android 12, using an A1111-like mock with a permanent hypernetworks 404: connection succeeds, embeddings preload continues, and each H-Net dialog opening in Txt2Img/Img2Img makes a fresh request and shows the empty state. LoRA fetches on opening as before.
• Actual SDNext/Neo backends and image generation were not tested.