feat(tools): persona-driven multi-domain corpus + model routing

Generalize the family-locked legal tools into caveauAI persona profiles
(client 57 chat profiles, resolved in-process via the chat_profiles bridge).
Each tool accepts an optional `profile` slug that scopes the corpus package(s),
search method, system prompt and synthesis model; omitting it falls back to the
family-legal package so existing behaviour is unchanged.

- dbnToolsResolvePersona / dbnToolsListPersonas / dbnToolsBootChatProfiles in
  bootstrap.php; new api/personas.php + dbn.list_personas MCP tool.
- LegalTools search/ask/corpusContextForSummarize and the BvjAnalyzer /
  LegalAnalysis / translate paths take the persona's packages + prompt + model.
- Persona <select> on ask/search/summarize (populated from api/personas.php).

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

api/personas.php

@@ -0,0 +1,16 @@
+<?php
+declare(strict_types=1);
+
+require_once __DIR__ . '/../includes/LegalTools.php';
+
+dbnToolsRequireMethod('GET');
+dbnToolsRequireAuth();
+
+$client   = dbnToolsRequireClient();
+$personas = dbnToolsListPersonas((int)$client['id']);
+
+dbnToolsRespond([
+    'ok'              => true,
+    'personas'       => $personas,
+    'default_persona' => dbnToolsDefaultPersonaSlug(),
+]);