Migrate app to SvelteKit remote functions

[nevthereal]

Summary

• Migrated server-driven route logic to SvelteKit remote functions across clubs, challenges, profile, and session flows.
• Removed many +page.server.ts and layout server modules in favor of colocated remote data access and actions.
• Refactored forms and shared UI primitives to match the new remote-function architecture.
• Updated project dependencies and SvelteKit tooling to current versions required by the migration.
• Cleaned up obsolete Drizzle migration artifacts and removed old superforms-based form components.

Testing

• Not run: automated tests were not executed in this pass.
• Not run: Playwright e2e suite was not executed.
• Not run: type-checking/build verification was not executed.
• Manual check recommended: navigate core flows for clubs, challenges, profile editing, and join/create forms to confirm remote functions behave as expected.

Summary by CodeRabbit

• Revert
  • Removed all database schema migrations and corresponding snapshots. This resets the database structure to an initial state, eliminating previously defined tables, relationships, and constraints from the migration history.

[nevthereal]

@coderabbitai review

[coderabbitai]

✅ Actions performed

Review triggered.

Note: CodeRabbit is an incremental review system and does not re-review already reviewed commits. This command is applicable only when automatic reviews are paused.