feat(tools): persona selector across standalone tools + dashboard chat

Wire the legal-domain persona picker into corpus, deep-research, korrespond and
the dashboard chat. Each endpoint reads the chosen profile, resolves its packages
against client 57, and scopes retrieval via package_ids (falling back to family
when omitted). New dashboard tenants now subscribe to all DBN domain packages so
persona switching survives the subscription intersection.

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

includes/DeepResearchAgent.php

@@ -36,7 +36,8 @@ final class DbnDeepResearchAgent
         string   $advocateRole = '',
         ?array   $priorContext = null,
         string   $branchNotes = '',
-        array    $subQuestionsOverride = []
+        array    $subQuestionsOverride = [],
+        ?string  $persona = null
     ): array {
         $seedQuery   = trim($seedQuery);
         $pastedText  = trim($pastedText);
@@ -50,7 +51,15 @@ final class DbnDeepResearchAgent
         }
 
         $client  = dbnToolsRequireClient();
-        $package = $this->requireFamilyPackage((int)$client['id']);
+        $personaResolved = dbnToolsResolvePersona((int)$client['id'], $persona);
+        $packageIds = array_values(array_filter(
+            array_map('intval', $personaResolved['package_ids'] ?? []),
+            static fn(int $id): bool => $id > 0
+        ));
+        if (!$packageIds) {
+            // Persona resolved without a package → fall back to the legacy family package.
+            $packageIds = [(int)$this->requireFamilyPackage((int)$client['id'])['id']];
+        }
 
         dbnToolsBootCaveau();
         $aiPortalRoot = dbnToolsAiPortalRoot();
@@ -230,7 +239,7 @@ final class DbnDeepResearchAgent
                     [
                         'search_private'         => false,
                         'search_shared'          => true,
-                        'package_ids'            => [(int)$package['id']],
+                        'package_ids'            => $packageIds,
                         'shared_doc_ids'         => $sharedDocIds,
                         'chunk_limit'            => $controls['chunk_limit'],
                         'search_method'          => 'hybrid',