Localize built-in UI and respond to appearance changes

[HituziANDO]

Problem

Default alert text, the release-notes title, and version labels are hard-coded in English. Blur and icon colors are selected once and do not reliably follow appearance changes while the view is visible.

Scope

• Move all built-in user-facing strings into a framework resource bundle.
• Ensure resources work through Swift Package Manager, CocoaPods, and the XCFramework.
• Keep every string overridable by the integrating application.
• Use dynamic system colors and materials or update them when traits change.

Acceptance criteria

• Built-in UI follows the device locale when no override is supplied.
• Resource lookup succeeds in every supported distribution format.
• Appearance changes update colors and material without recreating the controller.
• Existing custom text configuration remains supported.

Tests

• Verify at least two locales, fallback behavior, custom overrides, and runtime light/dark appearance changes.

Relevant files

• Framework/Sources/SwiftyUpdateKitConfig.swift
• Framework/Sources/SUK.swift
• Framework/Sources/ReleaseNotesController.swift
• Package.swift
• SwiftyUpdateKit.podspec