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>

korrespond.php

@@ -78,6 +78,13 @@ require_once __DIR__ . '/includes/layout.php';
                     </div>
                     <p class="upload-hint">Quick uses Claude Haiku 4.5 for drafting — fast and solid for standard correspondence. Thorough uses Claude Sonnet 4.6 — better at multi-statute cases, complex appeal grounds, and ECHR framing.</p>
 
+                    <!-- Domain persona -->
+                    <div class="control-row corpus-persona is-hidden" id="korrPersonaControl">
+                        <span class="control-label">Domain</span>
+                        <select id="korrPersonaSelect" class="adv-role-select" aria-label="Legal domain persona"></select>
+                        <small class="control-hint">Scopes the hard-RAG law retrieval to a legal domain.</small>
+                    </div>
+
                     <!-- Case context fields -->
                     <div class="dr-control-grid">
                         <div class="dr-control-card">