refactor(settings): fold Labs, Vorsorge, and Illness into the shell

Promote the three per-module customise surfaces from standalone
ModuleSettingsFrame pages to first-class Settings sections. They now
render inside the Settings shell — same left nav, heading, and chrome as
account / ai / integrations / notifications — instead of their own
back-button-and-title frame outside it.

Add labs, illness, and vorsorge to the slug registry (after mood) and to
SETTINGS_SECTIONS with FlaskConical / Thermometer / CalendarCheck icons.
labs and illness gate on their toggleable modules; vorsorge has no
module, so its entry is always shown. Three thin section components wrap
the existing LabsSettings / IllnessSettings / VorsorgeSettings content,
mirroring MedicationsSection / CoachSection.

Delete the three standalone /settings/{labs,vorsorge,illness} routes so
the wrench deep links resolve through the dynamic [section] route, and
drop ModuleSettingsFrame now that nothing renders it. Add the section
title / subtitle / description keys across all six locales and remove the
dead per-module *.settings.* blocks the old pages consumed.

src/components/module-list/module-settings-frame.tsx

@@ -1,42 +0,0 @@
-"use client";
-
-import type { ReactNode } from "react";
-
-import { SettingsHubBackLink } from "@/components/settings/settings-hub-back-link";
-import { SettingsSectionFrame } from "@/components/settings/settings-section-frame";
-
-/**
- * v1.18.6 (W8 / MOD-03) — heading frame for the per-module settings pages
- * (Vorsorge / Illness / Labs).
- *
- * Delegates to the shared `SettingsSectionFrame` so every settings page — the
- * 19 shell sections and these three per-module pages — renders one identical
- * heading frame. These pages stay out of the slug registry (their static
- * routes win over `/settings/[section]`), so they drive the frame's explicit
- * title/subtitle mode and supply the "return to the module" back-link through
- * the frame's `topSlot`, which sits above the heading.
- */
-export function ModuleSettingsFrame({
-  title,
-  description,
-  backHref,
-  backLabelKey,
-  children,
-}: {
-  title: string;
-  description: string;
-  /** Where the "← back" link returns to — the module's own page. */
-  backHref: string;
-  backLabelKey: string;
-  children: ReactNode;
-}) {
-  return (
-    <SettingsSectionFrame
-      title={title}
-      subtitle={description}
-      topSlot={<SettingsHubBackLink href={backHref} labelKey={backLabelKey} />}
-    >
-      {children}
-    </SettingsSectionFrame>
-  );
-}