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>

deep-research.php

@@ -25,6 +25,12 @@ require_once __DIR__ . '/includes/layout.php';
                     </div>
                     <p class="upload-hint">Azure mini is the default and finishes fastest. Azure full is the most thorough. Norwegian specialist v3 is a Qwen2.5 fine-tune optimised for barnevernsloven, ECHR, and forvaltningsloven — best for cases involving § 4-25, Strand Lobben, or procedural challenges.</p>
 
+                    <div class="control-row corpus-persona is-hidden" id="drPersonaControl">
+                        <span class="control-label">Domain</span>
+                        <select id="drPersonaSelect" class="drill-sort-select" aria-label="Legal domain persona"></select>
+                        <small class="control-hint">Scopes the corpus to a legal domain persona.</small>
+                    </div>
+
                     <div class="dr-slice-section">
                         <p class="control-label">Corpus slices</p>
                         <p class="upload-hint">Three core legal slices are on by default. Enable Hague Convention, Norwegian Courts, Bufdir guidance, or DBN&nbsp;Resources for more targeted research.</p>