perf(lite): skip BFS scratch-map fills when target is already in reach

route() cleared two BuildArea-sized dir/dist maps before discovering, on
the first queue element, that the actor already stands in reach of the
target. Run the same wall/decor/loc reach checks up front and return
"already reachable" without any fill or MOVE_OPCLICK packet, matching the
existing length<=0 no-packet behavior.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

server/webclient/src/lite/action-encoding.test.ts

@@ -27,6 +27,7 @@ import WordPack from '#/wordfilter/WordPack.js';
 
 import { loadCache } from './cache.js';
 import { LiteClient } from './LiteClient.js';
+import { tryMoveTo } from './movement.js';
 import { dispatch } from './protocol/incoming.js';
 
 const ORIGIN = process.env.LITE_TEST_ORIGIN ?? 'https://rs-sdk-demo.fly.dev';
@@ -276,4 +277,20 @@ describe('outgoing action encoding', () => {
         expect(r.g2()).toBe(3250);
         expect(r.at).toBe(c.out.pos);
     });
+
+    test('an actor already inside an NPC footprint needs no movement packet', () => {
+        if (!available) {
+            return;
+        }
+
+        const c = makeClient('bota');
+        c.collision[0] = new CollisionMap();
+        c.localPlayer!.routeX[0] = 50;
+        c.localPlayer!.routeZ[0] = 50;
+
+        const start = c.out.pos;
+        // A size-five NPC rooted at 48,48 contains the actor at 50,50.
+        expect(tryMoveTo(c, 48, 48, 5, 5, 0, 0, 0)).toBe(true);
+        expect(c.out.pos).toBe(start);
+    });
 });

server/webclient/src/lite/movement.ts

@@ -66,6 +66,32 @@ function route(
     const srcX = c.localPlayer.routeX[0];
     const srcZ = c.localPlayer.routeZ[0];
 
+    // The normal BFS performs these exact reach checks on its first queue
+    // element, after clearing two full BuildArea-sized scratch maps. Hot
+    // interactions such as the KBD spawn attack are deliberately staged
+    // inside the target footprint, so return the identical "already in
+    // reach" result before those O(scene) fills. As in the existing
+    // length<=0 branch below, no MOVE_OPCLICK packet is required here; the
+    // caller immediately emits the interaction op.
+    if (srcX === dx && srcZ === dz) {
+        return true;
+    }
+    if (locShape !== LocShape.WALL_STRAIGHT) {
+        if ((locShape < LocShape.WALLDECOR_STRAIGHT_OFFSET
+            || locShape === LocShape.CENTREPIECE_STRAIGHT)
+            && collisionMap.testWall(srcX, srcZ, dx, dz, locShape - 1, locAngle)) {
+            return true;
+        }
+        if (locShape < LocShape.CENTREPIECE_STRAIGHT
+            && collisionMap.testWDecor(srcX, srcZ, dx, dz, locShape - 1, locAngle)) {
+            return true;
+        }
+    }
+    if (locWidth !== 0 && locLength !== 0
+        && collisionMap.testLoc(srcX, srcZ, dx, dz, locWidth, locLength, forceapproach)) {
+        return true;
+    }
+
     dirMap.fill(0);
     distMap.fill(99999999);