feat(form-builder): wire D1 building blocks into ApplyBindings + add deadline wrapper

Per RFC-WS-6 §Q1 v1.3 addition 1, 4 + §Q3 v1.3 addition 2 + ARCH-BINDINGS §5.3.

- FormBindingApplicator::withDeadline(int) returns a clone configured to
  throw FormBindingApplicatorTimeoutException if apply() exceeds the
  deadline. Soft post-call microtime check; cannot interrupt mid-query
  but catches the long tail. apply() refactored to single-return so the
  deadline check sits at one site instead of duplicated.
- ApplyBindingsOnFormSubmit::handle:
  - Initial identity_match_status='pending' write inside inner
    transaction (when subject is or becomes a person) so HTTP response
    carries the right state for the IdentityMatchBanner first-paint
    copy. Final state comes from the queued TriggerPersonIdentityMatch
    (D2 Phase C).
  - Wraps apply() with config('form_builder.apply_deadline_seconds', 5).
  - Catch block uses FormBindingExceptionClassifier::classify to write
    failure_response_code in the outer transaction alongside
    apply_status=FAILED. submission_id from the exception (when in the
    binding-applicator hierarchy) is also captured in context JSON.

Tests added in Phase I.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

api/app/FormBuilder/Bindings/FormBindingApplicator.php

@@ -7,6 +7,7 @@ namespace App\FormBuilder\Bindings;
 use App\Enums\FormBuilder\BindingTargetType;
 use App\Enums\FormBuilder\FormFieldBindingMergeStrategy;
 use App\Exceptions\FormBuilder\FormBindingApplicatorException;
+use App\Exceptions\FormBuilder\FormBindingApplicatorTimeoutException;
 use App\Exceptions\FormBuilder\FormBindingInfraException;
 use App\Exceptions\FormBuilder\FormBindingSchemaConfigException;
 use App\FormBuilder\Purposes\PurposeRegistry;
@@ -28,6 +29,10 @@ use Throwable;
  *   - Q9: subject resolution via per-purpose PurposeSubjectResolver.
  *   - Q10: optional sectionId for future section-level apply.
  *   - Q12: hierarchical activity log via BindingActivityLogger.
+ *   - v1.3 Q1 add 4: optional deadline (withDeadline()) — soft post-call
+ *     microtime check throwing FormBindingApplicatorTimeoutException.
+ *     Cannot interrupt mid-query; intended to catch the long-tail of
+ *     slow applies before they hang the public flow.
  */
 // Not final + not readonly: listener tests need to override `apply()` for
 // throw-path coverage (Mockery can't mock final classes; PHP doesn't allow
@@ -35,6 +40,15 @@ use Throwable;
 // individually to preserve immutability.
 class FormBindingApplicator
 {
+    /**
+     * Per RFC-WS-6 §Q1 v1.3 addition 4 — soft deadline (seconds). NULL
+     * means "no deadline check" (default). Set via withDeadline() so the
+     * value travels with a clone and the original instance stays
+     * deadline-free for other callers (e.g. the retry-service path,
+     * which currently does not bound apply() — see ARCH-BINDINGS §5.3).
+     */
+    private ?int $deadlineSeconds = null;
+
     public function __construct(
         private readonly PurposeRegistry $purposeRegistry,
         private readonly BindingConflictResolver $conflictResolver,
@@ -42,11 +56,34 @@ class FormBindingApplicator
         private readonly BindingActivityLogger $activityLogger,
     ) {}
 
+    /**
+     * Returns a clone configured to throw FormBindingApplicatorTimeoutException
+     * if apply() exceeds the given deadline.
+     *
+     * Per RFC-WS-6 §Q1 v1.3 addition 4 + ARCH-BINDINGS §5.3.
+     *
+     * Implementation note: this is a soft post-call deadline check via
+     * microtime. It cannot interrupt mid-query — for that, configure MySQL
+     * connection timeouts at the database driver level. The soft deadline
+     * is sufficient to prevent runaway apply() calls from hanging the
+     * public flow indefinitely; a typical apply() takes <100ms, so a 5s
+     * deadline catches the long tail.
+     */
+    public function withDeadline(int $seconds): self
+    {
+        $clone = clone $this;
+        $clone->deadlineSeconds = $seconds;
+
+        return $clone;
+    }
+
     /**
      * @throws FormBindingApplicatorException
      */
     public function apply(FormSubmission $submission, ?string $sectionId = null): BindingPassResult
     {
+        $start = microtime(true);
+
         if (DB::transactionLevel() < 1) {
             throw new FormBindingInfraException(
                 submissionId: (string) $submission->id,
@@ -81,38 +118,61 @@ class FormBindingApplicator
                 provisionedSubjectId: null,
                 applications: [],
             );
-            $this->activityLogger->logPass($submission, $result);
+        } else {
+            $resolved = $this->conflictResolver->resolve($submission, $sectionId);
 
-            return $result;
-        }
-
-        $resolved = $this->conflictResolver->resolve($submission, $sectionId);
-
-        // Persist subject identity for the result + apply each binding.
-        $applications = [];
-        foreach ($resolved as $binding) {
-            // Skip identity-key bindings — the resolver already used them
-            // for subject lookup in EventRegistration's PersonProvisioner
-            // path. Writing them again is a no-op at best, a clobber at
-            // worst.
-            if ($binding->isIdentityKey) {
-                continue;
+            // Persist subject identity for the result + apply each binding.
+            $applications = [];
+            foreach ($resolved as $binding) {
+                // Skip identity-key bindings — the resolver already used them
+                // for subject lookup in EventRegistration's PersonProvisioner
+                // path. Writing them again is a no-op at best, a clobber at
+                // worst.
+                if ($binding->isIdentityKey) {
+                    continue;
+                }
+                $applications[] = $this->applyOne($subject, $binding);
             }
-            $applications[] = $this->applyOne($subject, $binding);
-        }
 
-        $result = new BindingPassResult(
-            formSubmissionId: (string) $submission->id,
-            provisionedSubjectType: $this->morphAlias($subject),
-            provisionedSubjectId: (string) $subject->getKey(),
-            applications: $applications,
-        );
+            $result = new BindingPassResult(
+                formSubmissionId: (string) $submission->id,
+                provisionedSubjectType: $this->morphAlias($subject),
+                provisionedSubjectId: (string) $subject->getKey(),
+                applications: $applications,
+            );
+        }
 
         $this->activityLogger->logPass($submission, $result);
 
+        $this->checkDeadline((string) $submission->id, $start);
+
         return $result;
     }
 
+    /**
+     * Throws FormBindingApplicatorTimeoutException if a deadline is
+     * configured and the elapsed wall-clock time exceeds it.
+     */
+    private function checkDeadline(string $submissionId, float $startMicrotime): void
+    {
+        if ($this->deadlineSeconds === null) {
+            return;
+        }
+
+        $elapsed = microtime(true) - $startMicrotime;
+        if ($elapsed > $this->deadlineSeconds) {
+            throw new FormBindingApplicatorTimeoutException(
+                submissionId: $submissionId,
+                message: sprintf(
+                    'FormBindingApplicator exceeded deadline of %ds (elapsed: %.2fs) for submission %s',
+                    $this->deadlineSeconds,
+                    $elapsed,
+                    $submissionId,
+                ),
+            );
+        }
+    }
+
     private function applyOne(Model $subject, ResolvedBinding $binding): BindingApplicationResult
     {
         try {