feat: Use @openshock/svelte-core shared JS library

[hhvrc]

Migrate the frontend onto the shared @openshock/svelte-core library:

• shadcn-svelte ui/ now imported via the $hadcn alias; local ui/ tree removed
• shared components (Code, Keyboard, metadata, svg, datetime-picker, dialog-manager, input fields, etc.) and modules (cn, pure utils, type guards, validators, shared types, is-mobile, pwned-passwords) now from $core; local copies deleted
• LightSwitch and PasswordInput rewired to the library's decoupled APIs (injected color-scheme; forgotHref/onPwnedCheckError)
• design-system theme via @import '@openshock/svelte-core/theme.css'
• add $core and $hadcn aliases pointing at the package's dist

App-coupled code (ControlModules, shares, Turnstile, errorGuards, usernameValidator, etc.) stays local.

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[stage-review]

Ready to review this PR? Stage has broken it down into 12 individual chapters for you:

	Title
1	Configure workspace and library aliases
2	Remove local shadcn and utility code
3	Migrate global styles and core utilities
4	Rewire API and SignalR to core library
5	Update core state and telemetry logic
6	Rewire shared components and inputs
7	Migrate app layouts and global components
8	Update admin and settings pages
9	Update hubs and shares pages
10	Update auth and terminal pages
11	Update meta routes and server endpoints
12	Other changes

_{Chapters generated by Stage for commit 3f7f7e5 on Jun 25, 2026 2:24pm UTC.}