Integrate dbn-legal-agent-v2: upgrade all v1 refs + add Korrespond legal-check

- Replace dbn-legal-agent with dbn-legal-agent-v2 in bootstrap.php
  (dbnToolsRunLegalCheck), DeepResearchAgent.php (interpretSeed,
  expandQueries, synthesis fallback, deploy label), BvjAnalyzerAgent.php
  (check_model label) — 8 locations total
- Add dbn-legal-agent-v2 legal threshold check to KorrespondAgent:
  called after selfCheck() in both generate() and refine(); result
  surfaced as legal_check[] in the API response
- Render legal_check card in korrespond.js using existing bvj-red-flag
  styles; shows only when non-empty
- Add .korr-legal-check CSS block in tools.css

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

advocate.php

@@ -16,6 +16,14 @@ require_once __DIR__ . '/includes/layout.php';
                         <button type="button" class="lang-btn" data-lang="pl">&#127477;&#127473; PL</button>
                     </div>
 
+                    <div class="korr-doc-links">
+                        <a href="/advocate-about.php" target="_blank">About this tool</a>
+                        <span aria-hidden="true">&middot;</span>
+                        <a href="/advocate-guide.php" target="_blank">User guide</a>
+                        <span aria-hidden="true">&middot;</span>
+                        <a href="/advocate-tech.php" target="_blank">How it works</a>
+                    </div>
+
                     <!-- Role selector — the defining field for advocate mode -->
                     <div class="adv-role-row">
                         <label class="control-label" for="advRoleSelect">Who are you representing?</label>