feat: refocus on drawings — code/ADA gated off, drawing-integrity wave, Brain-directed clarification

- ENABLE_CODE_REVIEW flag (default off): skips code/ADA/jurisdiction review
  path in both pipelines; nothing deleted, one env flag to restore.
- Per-sheet Drawing Integrity QA wave (agent + classic, default on):
  dangling refs, on-sheet contradictions, dimension sanity, missing sheet
  essentials, tag hygiene. New DrawingIntegrityAgent + classic stage.
- Broadened conflict critic: intra-sheet + same-discipline contradictions,
  not just cross-discipline.
- Wave 6.5 Brain-directed clarification (bounded hub-and-spoke): Brain names
  uncertain findings, verify_evidence requests route through the wave-5b
  verifier; refuted findings suppressed. One planning call + capped verifies,
  single iteration. Shared _build_verify_scopes across 5b and 6.5.
- Config knobs, .env.example, frontend copy, tests (182 passing).

frontend/index.html

@@ -111,7 +111,7 @@
     <input type="email" id="email" placeholder="you@firm.com" />
   </div>
   <details class="email-card" id="intake">
-    <summary style="cursor:pointer">Project details <span class="opt">(optional &mdash; improves code/ADA review)</span></summary>
+    <summary style="cursor:pointer">Project details <span class="opt">(optional)</span></summary>
     <input type="text" id="project_name" placeholder="Project name" style="width:100%;margin-top:8px" />
     <input type="text" id="address" placeholder="Project address" style="width:100%;margin-top:8px" />
     <input type="text" id="occupancy" placeholder="Occupancy (e.g. Business, Assembly)" style="width:100%;margin-top:8px" />
@@ -473,7 +473,7 @@ function render(rep){
   const issues=rep.validated_issues||[];
   if(issues.length){
     html+='<details open style="margin-top:24px"><summary><b>QAQC issues ('+issues.length+')</b> '+
-      '<span class="opt">conflicts + full-set + code/ADA + constructability, deduplicated</span></summary>';
+      '<span class="opt">conflicts + drawing integrity + full-set + constructability, deduplicated</span></summary>';
     for(const c of issues){
       const rs=c.review_state;
       html+='<div class="conflict '+esc(c.severity)+'">'+