feat(admin): bug-report toggle, unify "Trennen" button styling

Bucket E+F of the v1.4.3 polish pass.

**Disconnect-button styling unified.** Three integrations had three
different "Trennen" buttons: Withings used `outline` + `text-
destructive`; moodLog used solid `destructive` (red bg, white text);
the AI/Codex card used `ghost` + `text-destructive`. Same action,
three readings — confusing. All three now use the Withings pattern
(`outline` + `text-destructive`). The actual confirmation button
inside the AlertDialog keeps its solid-red treatment so the final
"yes, do it" still reads as a strong commit.

**Bug-report explicit on/off toggle.** Until v1.4.3 the bug-report
feature was implicitly gated on "is the GitHub token + repo
configured". An admin who wanted to *temporarily* hide the report
button (e.g. during a freeze window) had to clear the encrypted
token, forcing re-entry on resume — destructive for a reversible
intent. Migration `0027_bug_report_enabled_toggle` adds
`app_settings.bug_report_enabled BOOLEAN NOT NULL DEFAULT TRUE`,
the admin settings schema accepts `bugReportEnabled`, and a Switch
in the admin → Bug Report card lets the operator flip it.
`POST /api/bugreport` now returns 503 ("Bug reports are disabled by
the administrator") when the flag is off — the client already
renders a "not configured" screen on that status, so the report
button hides gracefully without further client-side wiring.

i18n keys added: `admin.bugReportEnabledLabel` + `…Description` in
both DE and EN.

Tests + typecheck green (671/671).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/app/api/admin/settings/route.ts

@@ -41,6 +41,7 @@ export const GET = apiHandler(async () => {
     bugReportConfigured: Boolean(
       settings?.githubIssueRepo && settings?.githubIssueTokenEncrypted,
     ),
+    bugReportEnabled: settings?.bugReportEnabled ?? true,
     reminderLateMinutes: settings?.reminderLateMinutes ?? 120,
     reminderMissedMinutes: settings?.reminderMissedMinutes ?? 240,
     moodLogGlobal: settings?.moodLogGlobal ?? true,
@@ -73,6 +74,7 @@ export const PUT = apiHandler(async (request: NextRequest) => {
     "umamiEnabled",
     "glitchtipEnabled",
     "moodLogGlobal",
+    "bugReportEnabled",
   ] as const;
   for (const field of booleanFields) {
     if (data[field] !== undefined) {
@@ -220,6 +222,7 @@ export const PUT = apiHandler(async (request: NextRequest) => {
     bugReportConfigured: Boolean(
       settings.githubIssueRepo && settings.githubIssueTokenEncrypted,
     ),
+    bugReportEnabled: settings.bugReportEnabled,
     reminderLateMinutes: settings.reminderLateMinutes,
     reminderMissedMinutes: settings.reminderMissedMinutes,
     moodLogGlobal: settings.moodLogGlobal,