chore(TRUEREF-0022): fix lint errors and update architecture docs

- Fix 15 ESLint errors across pipeline workers, SSE endpoints, and UI
- Replace explicit any with proper entity types in worker entries
- Remove unused imports and variables (basename, SSEEvent, getBroadcasterFn, seedRules)
- Use empty catch clauses instead of unused error variables
- Use SvelteSet for reactive Set state in repository page
- Fix operator precedence in nullish coalescing expression
- Replace $state+$effect with $derived for concurrency input
- Use resolve() directly in href for navigation lint rule
- Update ARCHITECTURE.md and FINDINGS.md for worker-thread architecture

src/routes/api/v1/api-contract.integration.test.ts

@@ -217,15 +217,6 @@ function seedEmbedding(client: Database.Database, snippetId: string, values: num
 		.run(snippetId, values.length, Buffer.from(Float32Array.from(values).buffer), NOW_S);
 }
 
-function seedRules(client: Database.Database, repositoryId: string, rules: string[]) {
-	client
-		.prepare(
-			`INSERT INTO repository_configs (repository_id, rules, updated_at)
-			 VALUES (?, ?, ?)`
-		)
-		.run(repositoryId, JSON.stringify(rules), NOW_S);
-}
-
 describe('API contract integration', () => {
 	beforeEach(() => {
 		db = createTestDb();

src/routes/repos/[id]/+page.svelte

@@ -2,6 +2,7 @@
 	import { goto } from '$app/navigation';
 	import { resolve as resolveRoute } from '$app/paths';
 	import { onMount } from 'svelte';
+	import { SvelteSet } from 'svelte/reactivity';
 	import type { PageData } from './$types';
 	import type { Repository, IndexingJob } from '$lib/types';
 	import ConfirmDialog from '$lib/components/ConfirmDialog.svelte';
@@ -48,7 +49,7 @@
 	// Discover tags state
 	let discoverBusy = $state(false);
 	let discoveredTags = $state<Array<{ tag: string; commitHash: string }>>([]);
-	let selectedDiscoveredTags = $state<Set<string>>(new Set());
+	let selectedDiscoveredTags = new SvelteSet<string>();
 	let showDiscoverPanel = $state(false);
 	let registerBusy = $state(false);
 
@@ -330,7 +331,7 @@
 			discoveredTags = (d.tags ?? []).filter(
 				(t: { tag: string; commitHash: string }) => !registeredTags.has(t.tag)
 			);
-			selectedDiscoveredTags = new Set(discoveredTags.map((t) => t.tag));
+			selectedDiscoveredTags = new SvelteSet(discoveredTags.map((t) => t.tag));
 			showDiscoverPanel = true;
 		} catch (e) {
 			errorMessage = (e as Error).message;
@@ -340,13 +341,11 @@
 	}
 
 	function toggleDiscoveredTag(tag: string) {
-		const next = new Set(selectedDiscoveredTags);
-		if (next.has(tag)) {
-			next.delete(tag);
+		if (selectedDiscoveredTags.has(tag)) {
+			selectedDiscoveredTags.delete(tag);
 		} else {
-			next.add(tag);
+			selectedDiscoveredTags.add(tag);
 		}
-		selectedDiscoveredTags = next;
 	}
 
 	async function handleRegisterSelected() {
@@ -381,7 +380,7 @@
 			activeVersionJobs = next;
 			showDiscoverPanel = false;
 			discoveredTags = [];
-			selectedDiscoveredTags = new Set();
+			selectedDiscoveredTags = new SvelteSet();
 			await loadVersions();
 		} catch (e) {
 			errorMessage = (e as Error).message;
@@ -550,7 +549,7 @@
 					onclick={() => {
 						showDiscoverPanel = false;
 						discoveredTags = [];
-						selectedDiscoveredTags = new Set();
+					selectedDiscoveredTags = new SvelteSet();
 					}}
 					class="text-xs text-blue-600 hover:underline"
 				>
@@ -649,7 +648,7 @@
 							<div class="flex justify-between text-xs text-gray-500">
 							<span>
 								{#if job?.stageDetail}{job.stageDetail}{:else}{(job?.processedFiles ?? 0).toLocaleString()} / {(job?.totalFiles ?? 0).toLocaleString()} files{/if}
-								{#if job?.stage}{' - ' + stageLabels[job.stage] ?? job.stage}{/if}
+								{#if job?.stage}{' - ' + (stageLabels[job.stage] ?? job.stage)}{/if}
 							</span>
 								<span>{job?.progress ?? 0}%</span>
 							</div>

src/routes/settings/+page.svelte

@@ -66,16 +66,12 @@
 	let saveError = $state<string | null>(null);
 	let saveStatusTimer: ReturnType<typeof setTimeout> | null = null;
 
-	let concurrencyInput = $state<number>(0);
+	let concurrencyInput = $derived(data.indexingConcurrency);
 	let concurrencySaving = $state(false);
 	let concurrencySaveStatus = $state<'idle' | 'ok' | 'error'>('idle');
 	let concurrencySaveError = $state<string | null>(null);
 	let concurrencySaveStatusTimer: ReturnType<typeof setTimeout> | null = null;
 
-	$effect(() => {
-		concurrencyInput = data.indexingConcurrency;
-	});
-
 	const currentSettings = $derived(settingsOverride ?? data.settings);
 	const activeProfile = $derived(currentSettings.activeProfile);
 	const activeConfigEntries = $derived(activeProfile?.configEntries ?? []);