feat(admin): manage quiz questions and dare intensity

Add a Quiz Questions content page (list/filter/create/edit/activate-
deactivate, no delete since quiz_answers reference questions by id),
route it under manage_questions, and add a sidebar entry.

Fix DaresPage so intensity (1-5) is editable and shown in the table;
previously every admin-created dare silently defaulted to intensity 1.

Add authored min/max intensity fields to DarePacksPage: no trigger or
worker in apps/api computes these columns, so they are admin-set
thresholds gating pack visibility, not derived aggregates. avg_intensity
is displayed read-only since nothing writes to it and it is not used
for filtering.

Extract dare intensity and quiz option validation into small lib
modules with focused unit tests.

apps/admin/src/lib/quizQuestions.ts

@@ -0,0 +1,31 @@
+// Quiz question options are constrained by the database check
+// `array_length(options, 1) between 2 and 4` (see
+// apps/api/drizzle/0019_quiz.sql). These helpers keep the admin form
+// validation consistent with that constraint.
+
+export const MIN_QUIZ_OPTIONS = 2;
+export const MAX_QUIZ_OPTIONS = 4;
+
+export interface QuizQuestionFormValues {
+    prompt_self: string;
+    prompt_guess: string;
+    options: string[];
+}
+
+/** Trim options and drop any that are empty. */
+export function sanitizeQuizOptions(options: string[]): string[] {
+    return options.map((option) => option.trim()).filter(Boolean);
+}
+
+/**
+ * Validate a quiz question form. Returns an error message, or null when the
+ * form is valid.
+ */
+export function validateQuizQuestionForm(form: QuizQuestionFormValues): string | null {
+    if (!form.prompt_self.trim()) return 'The "about yourself" prompt is required';
+    if (!form.prompt_guess.trim()) return 'The "about your partner" prompt is required';
+    const cleanedOptions = sanitizeQuizOptions(form.options);
+    if (cleanedOptions.length < MIN_QUIZ_OPTIONS) return `At least ${MIN_QUIZ_OPTIONS} options are required`;
+    if (cleanedOptions.length > MAX_QUIZ_OPTIONS) return `At most ${MAX_QUIZ_OPTIONS} options are allowed`;
+    return null;
+}