Add My Docs picker to deep-research, advocate, barnevernet, korrespond, citations

- PHP: Add docPickerSection (button + chips + hidden input) to all 5 tool pages
- JS: Send doc_ids in payload for deep-research, advocate, barnevernet, korrespond
- Backend: Inject selected corpus doc content into paste_text/narrative/notes via dbnToolsInjectDocContent
- Citations: Add upload zone (file → api/extract.php → textarea) + paste textarea with live Norwegian legal reference extraction (regex) + ref chips → title search; doc picker populates titleInput via MutationObserver

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

api/korrespond.php

@@ -80,6 +80,7 @@ try {
         'clarifications' => is_array($input['clarifications'] ?? null) ? $input['clarifications'] : [],
         'use_my_case'    => !empty($input['use_my_case']),
     ];
+    $intake['narrative'] = dbnToolsInjectDocContent($input, $intake['narrative']);
 
     $forceDraft = !empty($input['force_draft']);
     $hasClarif  = !empty($intake['clarifications']);
@@ -166,14 +167,14 @@ try {
     $ftUid = dbnToolsFreeTierCheck('korrespond');
     $ftRemaining = dbnToolsFreeTierDeduct($ftUid, 'korrespond');
     $creditDeducted = true;
-    if ($ftRemaining >= 0) {
-        header('X-Credits-Remaining: ' . $ftRemaining);
-    }
 
     // ── Pass 2: retrieve law → draft → self-check → translate ──────────────────
     $result = $agent->generate($intake, $classify, $emit);
     $result['ok']         = true;
     $result['latency_ms'] = (int)round((microtime(true) - $startTime) * 1000);
+    if ($ftRemaining >= 0) {
+        $result['balance'] = $ftRemaining;
+    }
 
     dbnToolsLogMetadata([
         'tool'         => 'korrespond',