Add scoped Agent-mode pipeline as experimental Classic fork.

Wire specialist waves, Brain consolidation, and Classic-compatible reports so Agent mode can run end-to-end via OpenRouter without changing the default Classic path.

Co-authored-by: Cursor <cursoragent@cursor.com>

backend/.env.example

@@ -4,6 +4,29 @@ AI_BASE_URL=https://openrouter.ai/api/v1
 AI_API_KEY=sk-or-...
 MODEL=google/gemini-2.5-pro
 
+# Optional Agent-mode OpenRouter model overrides (inherit MODEL/TEXT_MODEL when blank)
+AGENT_EXTRACT_MODEL=
+AGENT_INDEX_MODEL=
+AGENT_JURISDICTION_MODEL=
+AGENT_LINKER_MODEL=
+AGENT_CONFLICT_MODEL=
+AGENT_CODE_MODEL=
+AGENT_CONSTRUCT_MODEL=
+AGENT_COMPLETENESS_MODEL=
+AGENT_BRAIN_MODEL=
+AGENT_RFI_MODEL=
+
+# Agent-mode hard scope limits / concurrency
+AGENT_LINK_MAX_ASSERTIONS=60
+AGENT_CLUSTER_MAX_ASSERTIONS=24
+AGENT_CONFLICT_MAX_IMAGES=6
+AGENT_CODE_BATCH_SIZE=60
+AGENT_BRAIN_MAX_TOKENS=16384
+AGENT_LINK_CONCURRENCY=4
+AGENT_CONFLICT_CONCURRENCY=4
+AGENT_SPECIALIST_CONCURRENCY=4
+AGENT_RFI_CONCURRENCY=4
+
 # Pipeline tuning
 PDF_DPI=100
 MAX_PAGES=60