feat: upgrade to SvelteKit 3 and adapter-bun

Run the sveltekit-3 migration and finish its manual tasks:

- Move kit config into the sveltekit() Vite plugin; drop svelte.config.js
- Replace $lib with #lib subpath imports
- Declare env vars in src/env.ts and import them from $app/env/{private,public}
- Consolidate param matchers into src/params.ts
- Use error(status, message), Response.json, refreshAll and goto reset/shallow
- Fall back to a full page load when goto rejects a login return path

Switch from adapter-node to adapter-bun: the build script runs Vite under
Bun (the adapter requires it) and the image starts with `bun ./build`.
Runtime env names (PORT, BODY_SIZE_LIMIT, ADDRESS_HEADER, ...) are unchanged.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/lib/catch-em-all/PokemonDetails.svelte

@@ -1,8 +1,8 @@
 <script lang="ts">
-	import { pokemonImage } from '$lib/game-tracker/game-art';
-	import { Input } from '$lib/components/ui/input/index.js';
-	import { NativeSelect } from '$lib/components/ui/native-select/index.js';
-	import * as Table from '$lib/components/ui/table/index.js';
+	import { pokemonImage } from '#lib/game-tracker/game-art.js';
+	import { Input } from '#lib/components/ui/input/index.js';
+	import { NativeSelect } from '#lib/components/ui/native-select/index.js';
+	import * as Table from '#lib/components/ui/table/index.js';
 	let moveSearch = $state('');
 	let moveMethod = $state('all');
 
@@ -12,8 +12,8 @@
 		availabilityLabels,
 		availabilityValues,
 		obtainableAvailability
-	} from '$lib/availability';
-	import type { PokemonDetail } from '$lib/server/pokemon-detail';
+	} from '#lib/availability.js';
+	import type { PokemonDetail } from '#lib/server/pokemon-detail.js';
 
 	let {
 		number,

src/lib/catch-em-all/progress.test.ts

@@ -1,5 +1,5 @@
 import { describe, expect, it } from 'vitest';
-import { availabilityValues } from '$lib/availability';
+import { availabilityValues } from '#lib/availability.js';
 import { summarizeProgress } from './progress';
 
 const catchable = availabilityValues.indexOf('catchable');

src/lib/catch-em-all/progress.ts

@@ -1,4 +1,4 @@
-import { availabilityValues, obtainableAvailability } from '$lib/availability';
+import { availabilityValues, obtainableAvailability } from '#lib/availability.js';
 
 type PokemonWithEntries = {
 	id: number;