feat: replace 2 m placeholder with station pattern table from the workbook (Task 5)

Source: RAG 지보패턴현황_20260918.xlsx, sheet 참고_지보패턴현황, 당진방향 table
(4+740..5+500, 42 contiguous rows). Lining pattern (M column) per station now
drives the lining colour and the viewer readout. Daesan table kept as reference
only (WL-4 there, not applied). Drawing patterns E-1, E-2, RP-2, WL-3 are in
neither table and stay [미확정].

Co-Authored-By: Claude Haiku 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01A5Cun3RHQKna9qxE6ybZ4A

data/pattern_stations_dangjin.csv

@@ -0,0 +1,48 @@
+direction,source_row,sta_from,sta_to,length_m,lining_pattern,excavation,excavation_inherited,method,remark
+당진,55,4740.0,4745.0,5,개착부,,True,,개착부
+당진,56,4745.0,4763.0,18,P-3,NP-6,False,"상·하
+반단면",
+당진,57,4763.0,4785.0,22,WL-2,NP-5,False,,
+당진,58,4785.0,4796.0,11,WL-1,NP-5,True,,
+당진,59,4796.0,4839.0,43,D-2,NP-4,False,,
+당진,60,4839.0,4848.0,9,D-1,NP-4,True,,
+당진,61,4848.0,4857.0,9,C-2,NP-4,True,전단면,
+당진,62,4857.0,4862.0,5,C-1,NP-4,True,,
+당진,63,4862.0,4867.0,5,B-2,B-2,False,,
+당진,64,4867.0,4873.0,6,B-1,B-1,False,,
+당진,65,4873.0,4907.0,34,A,A,False,,
+당진,66,4907.0,4915.0,8,B-1,B-1,False,,
+당진,67,4915.0,4920.0,5,B-2,B-2,False,,
+당진,68,4920.0,4940.0,20,RP-1,B-2,True,,"대인용
+ 연결통로 접속부"
+당진,69,4940.0,4988.0,48,C-1,C-1,False,,
+당진,70,4988.0,4998.0,10,B-2,B-2,False,,
+당진,71,4998.0,5006.0,8,B-1,B-1,False,,
+당진,72,5006.0,5019.0,13,B-2,B-2,False,,
+당진,73,5019.0,5025.0,6,B-1,B-1,False,,
+당진,74,5025.0,5110.0,85,A,A,False,,
+당진,75,5110.0,5130.0,20,RP-1,A,True,,"차량용
+ 연결통로 접속부"
+당진,76,5130.0,5140.0,10,B-1,B-1,False,,
+당진,77,5140.0,5157.0,17,B-2,B-2,False,,
+당진,78,5157.0,5204.0,47,C-1,C-1,False,,
+당진,79,5204.0,5211.0,7,B-2,B-2,False,,
+당진,80,5211.0,5221.0,10,B-1,B-1,False,,
+당진,81,5221.0,5259.0,38,A,A,False,,
+당진,82,5259.0,5279.0,20,B-1,B-1,False,,
+당진,83,5279.0,5300.0,21,A,A,False,,
+당진,84,5300.0,5320.0,20,RP-1,A,True,,"대인용
+ 연결통로 접속부"
+당진,85,5320.0,5357.0,37,A,A,False,,
+당진,86,5357.0,5363.0,6,B-1,B-1,False,,
+당진,87,5363.0,5377.0,14,B-2,B-2,False,,
+당진,88,5377.0,5390.0,13,C-1,C-1,False,,
+당진,89,5390.0,5399.0,9,C-2,C-2,False,,
+당진,90,5399.0,5406.0,7,D-1,NP-4,False,"상·하
+반단면",
+당진,91,5406.0,5427.0,21,D-2,NP-4,True,,
+당진,92,5427.0,5446.0,19,D-1,NP-4,True,,
+당진,93,5446.0,5462.0,16,WL-2,NP-5,False,,
+당진,94,5462.0,5468.0,6,P-2,NP-6,False,,
+당진,95,5468.0,5495.0,27,P-3,NP-6,True,,
+당진,96,5495.0,5500.0,5,개착부,NP-6,True,,개착부