feat: stats csv export

[simonostendorf]

closes #921

[Copilot]

Pull Request Overview

Adds a CSV export for admin statistics and exposes it via the dashboard.

• New route and controller action to stream a CSV with global, per-event, per-group, per-slot, and per-course stats.
• Admin dashboard UI button to trigger the CSV download.
• CSV headers and rows assembled server-side and streamed to the client.

Reviewed Changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 10 comments.

File	Description
routes/web.php	Adds a GET route for downloading statistics, behind the view statistics ability.
resources/js/pages/Dashboard/Admin/Index.vue	Adds a button that opens the download URL in a new tab.
app/Http/Controllers/DashboardAdminController.php	Implements streamed CSV export with computed statistics across events, groups, slots, and courses.

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[Copilot]

Using utf8_decode here converts strings from UTF-8 to ISO-8859-1, which contradicts the declared UTF-8 charset and will corrupt non-ASCII characters. Remove utf8_decode and write UTF-8 directly; if Excel support is needed, write a UTF-8 BOM once before the first fputcsv (e.g., fputs($file, "\xEF\xBB\xBF")). Apply the same change to the later writes in this method.

[Copilot]

[nitpick] The logic to build $row is duplicated across event, group, and slot sections, making future changes error-prone. Extract a helper to assemble a stats row (given a registrations source and labels) to centralize the counting and formatting, then reuse it for events, groups, and slots.

[Copilot]

[nitpick] The logic to build $row is duplicated across event, group, and slot sections, making future changes error-prone. Extract a helper to assemble a stats row (given a registrations source and labels) to centralize the counting and formatting, then reuse it for events, groups, and slots.

Suggested change

	$row = [];
	// add basic stats
	$row['event_or_group'] = $event->name . ' - ' . $slot->name;
	$row['registered_users'] = $slot->registrations()->count();
	$row['present_users'] = $slot->registrations()->where('is_present', true)->count();
	$row['not_present_users'] = $slot->registrations()->where('is_present', false)->count();
	$row['present_percentage'] = ($row['registered_users'] > 0 ? round(($row['present_users'] / $row['registered_users']) * 100, 2) . '%' : '0%');
	// add requirements stats if event has requirements
	if ($event->has_requirements) {
	$row['fulfills_requirements'] = $slot->registrations()->where('fulfils_requirements', true)->count();
	$row['not_fulfills_requirements'] = $slot->registrations()->where('fulfils_requirements', false)->count();
	$row['fulfills_requirements_percentage'] = ($row['registered_users'] > 0 ? round(($row['fulfills_requirements'] / $row['registered_users']) * 100, 2) . '%' : '0%');
	} else {
	$row['fulfills_requirements'] = 'N/A';
	$row['not_fulfills_requirements'] = 'N/A';
	$row['fulfills_requirements_percentage'] = 'N/A';
	}
	// add alcohol stats if event consider alcohol
	if ($event->consider_alcohol) {
	$row['drinks_alcohol'] = $slot->registrations()->where('drinks_alcohol', true)->count();
	$row['drinks_no_alcohol'] = $slot->registrations()->where('drinks_alcohol', false)->count();
	$row['drinks_alcohol_percentage'] = ($row['registered_users'] > 0 ? round(($row['drinks_alcohol'] / $row['registered_users']) * 100, 2) . '%' : '0%');
	} else {
	$row['drinks_alcohol'] = 'N/A';
	$row['drinks_no_alcohol'] = 'N/A';
	$row['drinks_alcohol_percentage'] = 'N/A';
	}
	// add course stats
	foreach ($courses as $course) {
	$row['course_' . $course->abbreviation] = $slot->registrations()->whereHas('user', function ($query) use ($course) {
	$query->where('course_id', $course->id);
	})->count();
	}
	$row = $this->buildStatsRow(
	$slot->registrations(),
	$event->name . ' - ' . $slot->name,
	$event,
	$courses
	);