fix: Paket 0 – data integrity, security hardening and field usability

Backend
- Backup covers every Prisma model (bundle v3); a guard test fails for any
  new model that is neither backed up nor explicitly excluded. Unsealed
  bundles may only add rows to 27 legacy master/field tables and never
  overwrite; counters, ledgers, settings, roles etc. need a sealed file.
  Shared import limit BACKUP_MAX_IMPORT_BYTES (default 50 MB, max 256 MB)
  with warnings in log and UI; replaced document files are removed after
  commit.
- Post-commit side effects (automation, calendar sync, webhooks) run via
  runAfterCommit and never turn a committed write into a 500, so retries
  with the same Idempotency-Key no longer create duplicates.
- Calendar outbox is multi-replica safe: per-entry claims with stale
  takeover, revision-based settle, new Graph event only on 404/410,
  transactionId on create, 30 s Graph timeout, URL-encoded ids, GUID
  validation for groupId, "run now" in background and resets FAILED.
- Automation tasks are deduplicated under a row lock on the rule.
- Update DTOs follow one null rule: omitted = unchanged, null clears a
  nullable field, null on a required field is a 400.
- Varroa mites/day is recomputed on correction; withdrawal status is
  checked against the harvest date (?at=), bounded colonyIds; inspection
  create is audited; updates re-enqueue calendar entries.
- Dashboard, statistics and apiary/colony guards treat WEAK, CONSPICUOUS
  and QUEENLESS colonies as living.
- Prisma errors and body-parser errors are logged without query values or
  request bodies.
- Migration 20261012100000_calendar_sync_claims; schema index name aligned
  with the existing database object.

Frontend
- Sticky save bar sticks again (no scroll container ancestors, card uses
  overflow-clip), safe-area insets, scroll-padding, FAB hidden on forms,
  sticky desktop sidebar.
- Inspections record yes / no / not checked instead of silent defaults.
- All living colonies are selectable; shared RecordSelect, EnumSelect,
  ChoiceGroup and TriStateField replace per-page copies; selects show
  names instead of ids; labels point at real controls.
- Emptied optional fields are sent as null (emptyToNull) so every field
  can be cleared; dates default to the local day and are sent via
  toApiDate.
- Harvest withdrawal warning uses the harvest date; backup page warns when
  a backup outgrows the import limit and lists skipped tables.

Build and docs
- Docker builds fail unless lint, typecheck and unit tests pass.
- ARCHITECTURE.md updated (assumptions 9-12, 19-21, section 8) and spec
  docs/superpowers/specs/2026-10-12-plattform-rueckgrat-und-fahrplan-design.md
  for the backbone (api/worker/job roles, domain event outbox) and the
  feature roadmap T3-T7.

Co-Authored-By: Claude Opus 5.5 (1M context) <[email protected]>

ApiCore-Frontend/src/app/globals.css

@@ -181,6 +181,24 @@
   --shadow-soft: 0 1px 2px -1px oklch(0 0 0 / 25%), 0 4px 12px -4px oklch(0 0 0 / 30%);
 }
 
+/* ---------------------------------------------------------------------------
+   App chrome (see app/(app)/layout.tsx)
+   The page scrolls on the window. On phones a fixed bottom nav sits over its
+   lower edge, on iOS above the home indicator (needs viewport-fit=cover).
+   Content padding, the sticky save bar, the quick-add button and the focus
+   scroll-padding below all derive from these values, so they stay in step.
+   ------------------------------------------------------------------------ */
+:root {
+  --safe-area-bottom: env(safe-area-inset-bottom, 0px);
+  --safe-area-left: env(safe-area-inset-left, 0px);
+  --safe-area-right: env(safe-area-inset-right, 0px);
+  --bottom-nav-height: calc(4rem + var(--safe-area-bottom));
+  /* Sticky header (3.5rem) plus breathing room. */
+  --header-clearance: 4.5rem;
+  /* StickySubmit with its 48px button (~4.6rem) plus breathing room. */
+  --sticky-submit-clearance: 5.5rem;
+}
+
 @layer base {
   * {
     @apply border-border outline-ring/50;
@@ -190,6 +208,14 @@
   }
   html {
     @apply font-sans;
+    /* WCAG 2.4.11: a field scrolled into view by focus must not end up under
+       the sticky header, the bottom nav / quick-add button or the save bar. */
+    scroll-padding-top: var(--header-clearance);
+    scroll-padding-bottom: calc(var(--bottom-nav-height) + var(--sticky-submit-clearance));
+
+    @variant sm {
+      scroll-padding-bottom: calc(var(--sticky-submit-clearance) + var(--safe-area-bottom));
+    }
   }
   h1,
   h2,