feat(form-builder): form_field_conditional_logic_{groups,conditions} tables + OrganisationScope cap raise to 5

WS-5c commit 1 of 4 — relational infrastructure for the conditional-
logic tree that replaces form_fields.conditional_logic JSON (ARCH-
FORM-BUILDER §8; addendum Q3 WS-5c).

Tables: groups (nesting via parent_group_id) + conditions (leaves,
value JSON nullable for empty/not_empty). Simple FK to form_fields —
addendum Q3 explicitly excludes form_field_library from conditional_
logic scope, so no polymorphic morph here.

OrganisationScope cap raised 3 → 5 hops. The conditions chain is
4 hops (condition → group → field → schema → organisation_id column)
and the new cap gives headroom for future deeper trees without
denormalising form_field_id onto conditions.

Cascade observer (FormFieldChildTablesCascadeObserver) extended to
physically delete the new groups table on FormField delete (hard or
soft). Conditions cascade automatically via the group_id FK on the
groups table.

Factories: FormFieldConditionalLogicGroupFactory, FormFieldConditional
LogicConditionFactory, and FormFieldFactory::withConditionalLogic($tree)
for concise test fixtures.

Tests: 16 new under tests/Feature/FormBuilder/ConditionalLogic/
(relation, scope, cascade, enum catalogue). 3 new scope-cap tests in
ScopeLeakageTest verify 4/5-hop chains pass and 6-hop throws. Hardcoded
rollback step counts in WS-5a/b migration tests bumped for the 2 new
WS-5c migrations. Baseline 1104 → 1122 green (2988 → 3032 assertions).

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

api/app/Models/FormBuilder/FormField.php

@@ -119,6 +119,23 @@ final class FormField extends Model
         return $this->morphMany(FormFieldConfig::class, 'owner');
     }
 
+    public function conditionalLogicGroups(): HasMany
+    {
+        return $this->hasMany(FormFieldConditionalLogicGroup::class, 'form_field_id');
+    }
+
+    /**
+     * The tree root: the group with `parent_group_id IS NULL`. Fields
+     * without any conditional logic return null. Only one root is
+     * supported per field — enforced by the service layer's `replaceLogic`.
+     */
+    public function rootConditionalLogicGroup(): ?FormFieldConditionalLogicGroup
+    {
+        return $this->conditionalLogicGroups()
+            ->whereNull('parent_group_id')
+            ->first();
+    }
+
     /**
      * Nuanced activity log (ARCH §17.1; S1 Phase 4b). Callers choose which
      * events are worth logging — e.g. created/deleted/restored, field_type

api/app/Models/FormBuilder/FormFieldConditionalLogicCondition.php

@@ -0,0 +1,64 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Models\FormBuilder;
+
+use App\Enums\FormBuilder\FormFieldConditionalLogicConditionOperator;
+use App\Models\Scopes\OrganisationScope;
+use Illuminate\Database\Eloquent\Concerns\HasUlids;
+use Illuminate\Database\Eloquent\Factories\HasFactory;
+use Illuminate\Database\Eloquent\Model;
+use Illuminate\Database\Eloquent\Relations\BelongsTo;
+
+/**
+ * A leaf of the relational conditional-logic tree — one comparison
+ * of `(field_slug, operator, value)` against the current form values
+ * (ARCH-FORM-BUILDER §8).
+ *
+ * `value` is JSON nullable: scalar for most operators, array for
+ * `in`/`not_in`, null for `empty`/`not_empty`. Shape validation is
+ * enforced at the service layer (`FormFieldConditionalLogicService
+ * ::assertSpecsValid`), not the DB.
+ *
+ * Multi-tenancy chain is 4 hops (condition → group → field → schema →
+ * organisation_id column) — inside the WS-5c raised cap of 5.
+ */
+final class FormFieldConditionalLogicCondition extends Model
+{
+    use HasFactory;
+    use HasUlids;
+
+    protected $table = 'form_field_conditional_logic_conditions';
+
+    protected static function booted(): void
+    {
+        static::addGlobalScope(new OrganisationScope());
+    }
+
+    /** @return array{via: class-string, fk: string} */
+    public static function tenantScopeStrategy(): array
+    {
+        return ['via' => FormFieldConditionalLogicGroup::class, 'fk' => 'group_id'];
+    }
+
+    protected $fillable = [
+        'group_id',
+        'field_slug',
+        'comparison_operator',
+        'value',
+        'sort_order',
+    ];
+
+    /** @var array<string, string> */
+    protected $casts = [
+        'comparison_operator' => FormFieldConditionalLogicConditionOperator::class,
+        'value' => 'array',
+        'sort_order' => 'int',
+    ];
+
+    public function group(): BelongsTo
+    {
+        return $this->belongsTo(FormFieldConditionalLogicGroup::class, 'group_id');
+    }
+}

api/app/Models/FormBuilder/FormFieldConditionalLogicGroup.php

@@ -0,0 +1,76 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Models\FormBuilder;
+
+use App\Enums\FormBuilder\FormFieldConditionalLogicGroupOperator;
+use App\Models\Scopes\OrganisationScope;
+use Illuminate\Database\Eloquent\Concerns\HasUlids;
+use Illuminate\Database\Eloquent\Factories\HasFactory;
+use Illuminate\Database\Eloquent\Model;
+use Illuminate\Database\Eloquent\Relations\BelongsTo;
+use Illuminate\Database\Eloquent\Relations\HasMany;
+
+/**
+ * A node in the relational conditional-logic tree for a form field
+ * (ARCH-FORM-BUILDER §8). The root group carries the outer boolean
+ * operator (`all` / `any`); nested sub-groups link via
+ * `parent_group_id`. Leaves live in `FormFieldConditionalLogicCondition`.
+ *
+ * Multi-tenancy uses the Q2 declarative FK-chain resolver via
+ * `tenantScopeStrategy()`. The chain (group → field → schema →
+ * organisation_id) is 3 hops — comfortably inside the cap (5 hops as of
+ * WS-5c).
+ */
+final class FormFieldConditionalLogicGroup extends Model
+{
+    use HasFactory;
+    use HasUlids;
+
+    protected $table = 'form_field_conditional_logic_groups';
+
+    protected static function booted(): void
+    {
+        static::addGlobalScope(new OrganisationScope());
+    }
+
+    /** @return array{via: class-string, fk: string} */
+    public static function tenantScopeStrategy(): array
+    {
+        return ['via' => FormField::class, 'fk' => 'form_field_id'];
+    }
+
+    protected $fillable = [
+        'form_field_id',
+        'parent_group_id',
+        'operator',
+        'sort_order',
+    ];
+
+    /** @var array<string, string> */
+    protected $casts = [
+        'operator' => FormFieldConditionalLogicGroupOperator::class,
+        'sort_order' => 'int',
+    ];
+
+    public function formField(): BelongsTo
+    {
+        return $this->belongsTo(FormField::class, 'form_field_id');
+    }
+
+    public function parentGroup(): BelongsTo
+    {
+        return $this->belongsTo(self::class, 'parent_group_id');
+    }
+
+    public function childGroups(): HasMany
+    {
+        return $this->hasMany(self::class, 'parent_group_id');
+    }
+
+    public function conditions(): HasMany
+    {
+        return $this->hasMany(FormFieldConditionalLogicCondition::class, 'group_id');
+    }
+}

api/app/Models/Scopes/OrganisationScope.php

@@ -26,9 +26,15 @@ use Illuminate\Database\Eloquent\Scope;
  *         ['column' => 'organisation_id']  — direct scope column, OR
  *         ['via' => ParentModel::class, 'fk' => 'parent_id']  — walk to parent
  *       The resolver recurses through parents until it hits a column strategy
- *       or the legacy $organisationScopeColumn bridge. Cap at 3 hops; deeper
+ *       or the legacy $organisationScopeColumn bridge. Cap at 5 hops; deeper
  *       chains raise TenantScopeResolutionException.
  *
+ *       Cap raised from 3 to 5 in WS-5c (2026-04-26). Legitimate relational
+ *       trees — `form_field_conditional_logic_conditions → group → field →
+ *       schema → org` — exceed the original limit. Raising to 5 accommodates
+ *       this without denormalising `form_field_id` onto conditions (which
+ *       would introduce drift risk).
+ *
  *   (b) Legacy column property (pre-addendum — still supported so Person,
  *       Event, FestivalSection, etc. need not migrate in this work package):
  *       `public string $organisationScopeColumn = 'organisation_id'
@@ -43,7 +49,7 @@ use Illuminate\Database\Eloquent\Scope;
  */
 final class OrganisationScope implements Scope
 {
-    private const MAX_CHAIN_HOPS = 3;
+    private const MAX_CHAIN_HOPS = 5;
 
     public function __construct(
         private readonly ?string $organisationId = null,