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).

backend/.env.example

@@ -27,6 +27,23 @@ AGENT_CONFLICT_CONCURRENCY=4
 AGENT_SPECIALIST_CONCURRENCY=4
 AGENT_RFI_CONCURRENCY=4
 
+# -- Review focus toggles -------------------------------------------
+# ENABLE_CODE_REVIEW: run the code/ADA/jurisdiction review path (both pipelines).
+#   Default OFF - the product focuses on drawing integrity and cross-discipline
+#   coordination, not code/accessibility compliance. Set to 1 to restore it.
+ENABLE_CODE_REVIEW=false
+# ENABLE_DRAWING_INTEGRITY: per-sheet Drawing Integrity QA wave (both pipelines).
+#   The drawing-focused pass - dangling references, on-sheet contradictions,
+#   dimension sanity, missing sheet essentials, tag hygiene. Default ON.
+ENABLE_DRAWING_INTEGRITY=true
+AGENT_INTEGRITY_MODEL=
+AGENT_INTEGRITY_CONCURRENCY=4
+AGENT_INTEGRITY_MAX_IMAGES=1
+AGENT_INTEGRITY_MAX_ASSERTIONS=80
+INTEGRITY_MAX_TOKENS=16384
+# Skip sheets with fewer than this many extracted objects (too sparse to check)
+INTEGRITY_MIN_ASSERTIONS=3
+
 # Agent-mode human-review gate (pipeline stops after Brain until a human reviews)
 AGENT_REQUIRE_REVIEW=true
 # Max clean clusters added to the review queue as non-blocking spot-checks
@@ -79,6 +96,14 @@ AGENT_VERIFY_SEVERITIES=critical,high
 AGENT_VERIFY_REASONING_EFFORT=low
 VERIFY_MAX_TOKENS=8192
 
+# Wave 6.5 Brain-directed clarification (bounded hub-and-spoke). After the Brain
+# merge, the Brain names findings it is unsure about; verify_evidence requests
+# route back through the wave-5b verifier. One planning call + at most
+# BRAIN_CLARIFY_MAX_REQUESTS verifications, single iteration. Default ON.
+ENABLE_BRAIN_CLARIFY=true
+BRAIN_CLARIFY_MAX_REQUESTS=8
+BRAIN_CLARIFY_MAX_TOKENS=4096
+
 # Text-layer grounding (deterministic PDF text layer via PyMuPDF)
 # TEXT_LAYER_ENABLED: master switch for text-layer extraction/grounding
 # TEXT_LAYER_MIN_CHARS: below this per page the sheet stays vision-only