fix: make all CI jobs pass (integration, ui) and restore prefix dialog reset

Three failing test suites blocked CI. All three were test defects, not
application bugs.

Integration tests (integration/database.test.ts)
------------------------------------------------
The suite set NODE_ENV=test, which makes cache.cached() short-circuit both
its Redis read (src/lib/cache.ts:226) and its write (:249). A suite whose
stated purpose is exercising the real Redis path therefore never touched
Redis. Switched to NODE_ENV=development, the only non-production value
src/env.ts accepts, so the shared-cache code paths are genuinely covered.

Three assertions then needed correcting for real Redis semantics:

- `await cache.cached(...)` followed by `.resolves` can never hold: await
  yields a value, not a Promise. Assert the value directly.
- A cached negative result is stored as the JSON encoding of null, so
  `redis.get(key)` returns "null", not null.
- The news negative-cache key does not exist at all, so `ttl()` returned -2.
  Now that the write path is live the key is created and the TTL assertion
  holds as originally written.

UI tests (src/app/admin/prefixes/prefix-dialog.tsx)
---------------------------------------------------
The form-reset effect had `isOpen` removed from its dependency array. The
component returns null when closed, so the effect only ever ran on mount:
reopening the dialog no longer cleared the fields and a dismissed-but-
unsaved edit reappeared. Two tests in e2e/ui/unsaved-changes.spec.ts caught
this. Restored the dependency and documented why it is load-bearing.

The remaining edits in this branch drop stale biome-ignore comments that
suppressed useExhaustiveDependencies and noArrayIndexKey diagnostics. Where
the suppression had been load-bearing for behaviour, the underlying
dependency is now listed explicitly rather than silenced.

Verified: check (toolchain, audit, lint, i18n, typecheck), unit 3315
passed, integration 20 passed, UI 72 passed / 2 skipped.

integration/database.test.ts

@@ -156,7 +156,14 @@ beforeAll(async () => {
 	process.env.REDIS_URL = `redis://:${redisPassword}@${redisContainer.getHost()}:${redisContainer.getMappedPort(6379)}/0`;
 	delete process.env.SKIP_ENV_VALIDATION;
 	delete process.env.OPENAI_API_KEY;
-	Object.assign(process.env, { NODE_ENV: "test" });
+	// Deliberately NOT "test": cache.cached() short-circuits its Redis read and
+	// write whenever NODE_ENV === "test" (see refresh() in src/lib/cache.ts).
+	// This suite exists to exercise the real Redis path, so it runs under a
+	// value that leaves Redis enabled. "development" is used because it is the
+	// only non-production value src/env.ts accepts. Vitest's own environment is
+	// still configured via vitest.integration.config.ts. Object.assign is used
+	// because process.env.NODE_ENV is typed read-only.
+	Object.assign(process.env, { NODE_ENV: "development" });
 	process.env.HOTEL_NAME = "Integration";
 
 	await connection.query(
@@ -380,9 +387,10 @@ describe("Redis application cache", () => {
 		let fetches = 0;
 		const fetch = async () => ({ revision: ++fetches });
 		expect(await cache.cached(key, 60_000, fetch)).toEqual({ revision: 1 });
+		// Second read is served from cache, so the origin is not consulted again.
 		expect(
-			await cache.cached(key, 60000, async () => ({ revision: 1 })),
-		).resolves.toMatchObject({ revision: 1 });
+			await cache.cached(key, 60_000, fetch),
+		).toEqual({ revision: 1 });
 		expect(await appRedis?.ttl(key)).toBeGreaterThan(0);
 		cache.invalidateMemory(key);
 		expect(await cache.cached(key, 60_000, fetch)).toEqual({ revision: 1 });
@@ -403,6 +411,9 @@ describe("Redis application cache", () => {
 		expect(await cache.cached(first, 60_000, async () => "updated")).toBe(
 			"updated",
 		);
+		// `second`'s memory copy was dropped too, but its Redis entry survives, so
+		// the read is served from the shared cache and never recomputes. This is
+		// what makes the two entries independent.
 		expect(await cache.cached(second, 60_000, async () => "wrong")).toBe(
 			"second",
 		);
@@ -620,9 +631,12 @@ describe("real news publication, scheduling and cache delivery", () => {
 		expect(existing.status).toBe("draft");
 		expect(existing.publishedAt).toBeNull();
 		expect(await publicNews.getPublishedArticle(existing.slug)).toBeNull();
+		// A draft has no public article, so this read is a negative result that
+		// gets cached. Asserting both the payload and the TTL is what proves the
+		// "never leak an unpublished article" contract survives in Redis.
 		const negativeRevision = await appRedis?.get(NEWS_REVISION_KEY);
 		const negativeKey = `news:${negativeRevision}:article:v2:slug:${existing.slug}`;
-		expect(await appRedis?.get(negativeKey)).toBeNull();
+		expect(await appRedis?.get(negativeKey)).toBe("null");
 		expect(await appRedis?.ttl(negativeKey)).toBeGreaterThan(0);
 
 		const body = `<p>${"Contenuto completo è 📰 ".repeat(4000)}</p>`;
@@ -839,7 +853,8 @@ describe("real news publication, scheduling and cache delivery", () => {
 		expect(await publicNews.getPublishedArticle(existing.slug)).toBeNull();
 		const negativeRevision = await redis.get(NEWS_REVISION_KEY);
 		const negativeKey = `news:${negativeRevision}:article:v2:slug:${existing.slug}`;
-		expect(await redis.get(negativeKey)).toBeNull();
+		// Cached negative results are stored as the JSON encoding of null.
+		expect(await redis.get(negativeKey)).toBe("null");
 		const publish = articleForm({
 			id: String(existing.id),
 			baseToken: articleEditToken(existing),