feat(helpdesk): add handover protocol management

Implement handover protocols as a new entity in the helpdesk module,
allowing users to create fillable protocol records from admin-defined
software product schemas.

Key additions:
- DB migration (helpdesk_handovers table) with tenant scope
- HandoverService with status workflow (draft/in_progress/completed/archived)
- Three-tier permissions (view/create/manage)
- Two-step creation wizard (Stripe-style assistant)
- Grid.js list page with search and status filter
- Edit/detail page with aside metadata and status controls
- Reusable core autocomplete lookup component (app-lookup-field)
- Debitor lookup data endpoint for autocomplete
- Dynamic form rendering from schema snapshots
- 11 PHPUnit tests for HandoverService
- DE+EN i18n translations (48 keys each)

Also includes: PHPStan fixes (dead code removal, stale baseline cleanup),
software product edit title improvement, fieldset simplification,
and Stripe-style hover for schema preview.

Workflow: HD-HANDOVERS-001 (.agents/runs/HD-HANDOVERS-001/)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

web/css/components/app-lookup-field.css

@@ -0,0 +1,147 @@
+@layer components {
+  /*
+   * Autocomplete lookup field.
+   *
+   * A text input with a dropdown list of search results.
+   * Driven by data attributes via app-lookup-field.js.
+   */
+
+  .app-lookup-field {
+    position: relative;
+  }
+
+  /* ── Input wrapper ──────────────────────────────────────────────────── */
+
+  .app-lookup-field-input-wrap {
+    position: relative;
+    display: flex;
+    align-items: center;
+  }
+
+  .app-lookup-field-input {
+    padding-right: 2.5rem;
+    margin-bottom: 0;
+  }
+
+  .app-lookup-field-input[aria-expanded="true"] {
+    border-bottom-left-radius: 0;
+    border-bottom-right-radius: 0;
+    border-color: var(--app-primary, #635bff);
+  }
+
+  /* ── Clear / spinner icons ──────────────────────────────────────────── */
+
+  .app-lookup-field-indicator {
+    position: absolute;
+    right: 0.625rem;
+    top: 50%;
+    transform: translateY(-50%);
+    display: flex;
+    align-items: center;
+    justify-content: center;
+    width: 1.5rem;
+    height: 1.5rem;
+    pointer-events: none;
+    color: var(--app-muted-color);
+  }
+
+  .app-lookup-field-clear {
+    pointer-events: auto;
+    cursor: pointer;
+    background: none;
+    border: none;
+    padding: 0;
+    color: var(--app-muted-color);
+    font-size: var(--text-base, 1rem);
+    line-height: var(--leading-none);
+    transition: color 0.15s ease;
+  }
+
+  .app-lookup-field-clear:hover {
+    color: var(--app-color);
+  }
+
+  .app-lookup-field-spinner {
+    width: 1rem;
+    height: 1rem;
+    border: 2px solid var(--app-border);
+    border-top-color: var(--app-primary, #635bff);
+    border-radius: 50%;
+    animation: app-lookup-spin 0.6s linear infinite;
+  }
+
+  @keyframes app-lookup-spin {
+    to { transform: rotate(360deg); }
+  }
+
+  /* ── Dropdown ───────────────────────────────────────────────────────── */
+
+  .app-lookup-field-dropdown {
+    position: absolute;
+    top: 100%;
+    left: 0;
+    right: 0;
+    z-index: 100;
+    background: var(--app-card-background-color, #fff);
+    border: 1px solid var(--app-primary, #635bff);
+    border-top: none;
+    border-radius: 0 0 var(--app-border-radius) var(--app-border-radius);
+    box-shadow: 0 4px 12px rgb(0 0 0 / 0.08);
+    max-height: 16rem;
+    overflow-y: auto;
+    overscroll-behavior: contain;
+    list-style: none;
+    margin: 0;
+    padding: 0.25rem 0;
+  }
+
+  .app-lookup-field-dropdown[hidden] {
+    display: none;
+  }
+
+  /* ── Option items ───────────────────────────────────────────────────── */
+
+  .app-lookup-field-option {
+    display: flex;
+    flex-direction: column;
+    gap: 0.125rem;
+    padding: 0.5rem 0.75rem;
+    cursor: pointer;
+    font-size: var(--text-sm, 0.875rem);
+    color: var(--app-color);
+    transition: background-color 0.1s ease;
+  }
+
+  .app-lookup-field-option:hover,
+  .app-lookup-field-option[aria-selected="true"] {
+    background: color-mix(in srgb, var(--app-primary, #635bff) 8%, transparent);
+  }
+
+  .app-lookup-field-option[aria-selected="true"] {
+    color: var(--app-primary, #635bff);
+  }
+
+  .app-lookup-field-option-label {
+    font-weight: var(--font-medium, 500);
+  }
+
+  .app-lookup-field-option-meta {
+    font-size: var(--text-xs, 0.75rem);
+    color: var(--app-muted-color);
+  }
+
+  /* ── Empty / error messages ─────────────────────────────────────────── */
+
+  .app-lookup-field-message {
+    padding: 0.75rem;
+    font-size: var(--text-sm, 0.875rem);
+    color: var(--app-muted-color);
+    text-align: center;
+  }
+
+  /* ── Selected state ─────────────────────────────────────────────────── */
+
+  .app-lookup-field-input[data-lookup-selected] {
+    background: var(--app-card-background-color, #fff);
+  }
+}