fix(agent-office): critical bug fixes from code review — wall pathfinding, drag/click, DPR, culling

- Pathfinder.setBlocked: remove blocked.clear() to preserve wall tiles set by setWalls()
- Pathfinder.findPath: fix dead-code goal exception — remove redundant isBlocked check, keep goal-tile exception in single guard
- OfficeRenderer: track mouseDownPos/_wasDragging; expose wasDragging() method for click-after-drag suppression
- OfficeRenderer._render: track _lastDpr to detect monitor DPR changes; use setTransform instead of scale to avoid accumulation
- TileMap.render: use clientWidth/clientHeight for viewport culling (CSS space, not buffer pixels)
- TaskTab: wrap JSON.parse in try/catch to prevent crash on malformed result_data

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/pages/agent-office/canvas/OfficeRenderer.js

@@ -48,6 +48,11 @@ export class OfficeRenderer {
     // 게임 루프
     this._lastTime = 0;
     this._animId = null;
+    this._lastDpr = window.devicePixelRatio || 1;
+
+    // 드래그 감지
+    this._mouseDownPos = { x: 0, y: 0 };
+    this._wasDragging = false;
 
     // 이벤트
     this._setupInputHandlers();
@@ -91,12 +96,17 @@ export class OfficeRenderer {
       if (e.button === 0) {
         this._isPanning = true;
         this._panStart = { x: e.clientX - this.panX, y: e.clientY - this.panY };
+        this._mouseDownPos = { x: e.clientX, y: e.clientY };
+        this._wasDragging = false;
       }
     });
     this._onMouseMove = (e) => {
       if (this._isPanning) {
         this.panX = e.clientX - this._panStart.x;
         this.panY = e.clientY - this._panStart.y;
+        const dx = e.clientX - this._mouseDownPos.x;
+        const dy = e.clientY - this._mouseDownPos.y;
+        if (Math.abs(dx) > 5 || Math.abs(dy) > 5) this._wasDragging = true;
       }
     };
     this._onMouseUp = () => {
@@ -244,11 +254,13 @@ export class OfficeRenderer {
     // 캔버스 크기 조정
     const displayW = this.canvas.clientWidth;
     const displayH = this.canvas.clientHeight;
-    if (this.canvas.width !== displayW * dpr || this.canvas.height !== displayH * dpr) {
+    if (this.canvas.width !== displayW * dpr || this.canvas.height !== displayH * dpr || this._lastDpr !== dpr) {
       this.canvas.width = displayW * dpr;
       this.canvas.height = displayH * dpr;
-      ctx.scale(dpr, dpr);
+      this._lastDpr = dpr;
     }
+    // setTransform 방식으로 누적 없이 항상 올바른 변환 적용
+    ctx.setTransform(dpr, 0, 0, dpr, 0, 0);
 
     ctx.imageSmoothingEnabled = false;
     ctx.clearRect(0, 0, displayW, displayH);
@@ -287,6 +299,9 @@ export class OfficeRenderer {
     }
   }
 
+  /** 드래그 여부 반환 (클릭 이벤트 필터링용) */
+  wasDragging() { return this._wasDragging; }
+
   /** 리사이즈 처리 */
   resize() {
     // 다음 프레임에서 자동 조정됨 (_render에서 크기 체크)