fix: Terraform Agent uses SQLite RAG only, terminal shows errors properly

- Skip ADB vector search for Terraform Agent (uses local SQLite resource reference instead)
- Show error message in terminal when plan fails validation (no more stuck "Aguardando execução")
- Write region validation error to plan_output field for terminal display
- Fix Plan/Re-plan button visibility for all workspace states (including stuck planning/applying)

backend/app.py

@@ -3962,7 +3962,7 @@ async def _chat_background(mid: str, sid: str, msg: ChatMsg, user: dict, genai_c
                 log.info(f"RAG: filtering by tenancy '{rag_tenancy}'")
 
         rag_context = ""
-        adb_cfgs = _get_active_adb_configs(user["id"])
+        adb_cfgs = _get_active_adb_configs(user["id"]) if agent_type != "terraform" else []
         if adb_cfgs:
             all_documents = []
             for adb_cfg in adb_cfgs:
@@ -5176,8 +5176,8 @@ async def _terraform_exec(wid: str, action: str, user: dict):
             )
             log.warning(f"Workspace {wid}: missing variable 'region' — blocking plan")
             with db() as c:
-                c.execute("UPDATE terraform_workspaces SET status='failed', error=?, updated_at=datetime('now') WHERE id=?",
-                          (error_msg, wid))
+                c.execute("UPDATE terraform_workspaces SET status='failed', plan_output=?, error=?, updated_at=datetime('now') WHERE id=?",
+                          (error_msg, error_msg, wid))
             return
         region_value = 'var.region'