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/routes/projects/game-tracker/osu/+page.server.ts

@@ -1,8 +1,8 @@
 import { and, desc, eq } from 'drizzle-orm';
 import { fail } from '@sveltejs/kit';
-import { db } from '$lib/server/db';
-import { osuEntries } from '$lib/server/db/schema';
-import { allowedOsuUrl, boundedInteger, validDate } from '$lib/game-tracker/journal';
+import { db } from '#lib/server/db/index.js';
+import { osuEntries } from '#lib/server/db/schema/index.js';
+import { allowedOsuUrl, boundedInteger, validDate } from '#lib/game-tracker/journal.js';
 import type { Actions, PageServerLoad } from './$types';
 
 export const load: PageServerLoad = async ({ locals }) => ({

src/routes/projects/game-tracker/osu/+page.svelte

@@ -6,18 +6,18 @@
 	});
 	import { resolve } from '$app/paths';
 	import { enhance } from '$app/forms';
-	import * as Dialog from '$lib/components/ui/dialog/index.js';
-	import * as AlertDialog from '$lib/components/ui/alert-dialog/index.js';
-	import * as Tabs from '$lib/components/ui/tabs/index.js';
-	import * as Table from '$lib/components/ui/table/index.js';
-	import { Button } from '$lib/components/ui/button/index.js';
-	import { Input } from '$lib/components/ui/input/index.js';
-	import { Textarea } from '$lib/components/ui/textarea/index.js';
-	import { NativeSelect } from '$lib/components/ui/native-select/index.js';
-	import { Checkbox } from '$lib/components/ui/checkbox/index.js';
-	import { Badge } from '$lib/components/ui/badge/index.js';
-	import GameLogo from '$lib/game-tracker/GameLogo.svelte';
-	import ProgressMeter from '$lib/game-tracker/ProgressMeter.svelte';
+	import * as Dialog from '#lib/components/ui/dialog/index.js';
+	import * as AlertDialog from '#lib/components/ui/alert-dialog/index.js';
+	import * as Tabs from '#lib/components/ui/tabs/index.js';
+	import * as Table from '#lib/components/ui/table/index.js';
+	import { Button } from '#lib/components/ui/button/index.js';
+	import { Input } from '#lib/components/ui/input/index.js';
+	import { Textarea } from '#lib/components/ui/textarea/index.js';
+	import { NativeSelect } from '#lib/components/ui/native-select/index.js';
+	import { Checkbox } from '#lib/components/ui/checkbox/index.js';
+	import { Badge } from '#lib/components/ui/badge/index.js';
+	import GameLogo from '#lib/game-tracker/GameLogo.svelte';
+	import ProgressMeter from '#lib/game-tracker/ProgressMeter.svelte';
 	import type { PageProps } from './$types';
 	let { data, form }: PageProps = $props();
 	type Entry = (typeof data.entries)[number];
@@ -72,7 +72,7 @@
 
 <div class="mx-auto max-w-6xl px-3 py-4 sm:px-5">
 	<a
-		href={resolve('/projects/game-tracker')}
+		href={resolve('projects/game-tracker')}
 		class="text-sm text-muted-foreground hover:text-foreground">← game tracker</a
 	>
 	<div class="mt-3 flex flex-wrap items-center gap-3">
@@ -95,7 +95,7 @@
 		>
 	</div>
 	{#if !data.user}<p class="mt-6">
-			<a class="underline" href={resolve('/login?returnTo=/projects/game-tracker/osu')}>Sign in</a> to
+			<a class="underline" href={resolve('login?returnTo=/projects/game-tracker/osu')}>Sign in</a> to
 			start your training journal.
 		</p>{/if}
 	{#if form?.message && !open && !deleteOpen}<p class="mt-4 text-destructive" role="alert">