We need respond by creating index.html in current dir. Need inspect? Need create self-contained single-page web app. Need use tools. Need ensure no external resources. Full-screen flocking simulation boids separation alignment cohesion, oriented triangles, smooth steering, flee mouse cursor. Need maybe implement HTML/CSS/JS. Need likely just write file. Need maybe verify present. Since current /tmp/ws. Need use write. Need craft high-quality code.

Need be careful with final concise. Need maybe no analysis? We can include code? Need use write. Let's draft.

Need implement full-screen canvas, no external. Boids class. Use requestAnimationFrame. Mouse flee. Separation/alignment/cohesion. Smooth steering via acceleration/velocity capped. Oriented triangles with heading. Full-screen responsive. Maybe options? User didn't ask controls but can include small UI overlay? Maybe okay. Single page. Need maybe no network. Need "full-screen" maybe body margin 0, canvas fixed. Need triangles.

Need write index.html. Need maybe include accessibility? Not necessary.

Let's craft robust JS:
- canvas, ctx, devicePixelRatio scaling.
- resize: canvas.width = innerWidth*dpr, canvas.height = innerHeight*dpr; ctx.setTransform(dpr,0,0,dpr,0,0)
- constants: boidCount = maybe based on area: Math.min(260, Math.max(90, Math.floor(innerWidth*innerHeight/9000)))
- Boid {x,y,vx,vy,angle, hue}
- params:
maxSpeed 3.2, maxForce 0.08, neighborDist 70, separationDist 34, mouseFleeDist 170, mouseFleeStrength 1.4
- For each boid compute separation, align, cohesion:
loop all pairs O(n^2) okay for 200.
distSq < neighborDist^2. For separation if distSq < sepDist^2, diff = away normalized / sqrt? use diff = (b.x - other.x)/d etc; sum; countSep.
alignment sum vx/vy; cohesion sum positions.
After sums:
if alignCount >0: desired = average velocity normalized * maxSpeed; steer = desired - velocity; apply with maxForce
cohesion: desired = to center normalized * maxSpeed; steer...
separation: desired = avg separation normalized * maxSpeed; steer...
mouse: if distance < mouseFleeDist: desired = away from mouse normalized * maxSpeed*1.35, steer with maybe maxForce*2.5.
apply force with limit; update velocity, speed cap, position wrap? Flocking better wrap edges; but mouse full screen. Use wrap with margin maybe 10; if x < -margin -> width+margin etc.
- Smooth steering: acceleration and maxForce.
- Draw:
ctx.fillStyle maybe dark gradient.
draw trails? full-screen no. Could use rgba background to create trails? But full-screen simulation. If using clearRect. Draw background gradient.
for each boid draw triangle:
angle = atan2(vy,vx)
size = 8
ctx.translate, rotate; path: tip at size*1.4, left -size*0.8 ± size*0.55, fillStyle based on speed/hue. Maybe add stroke.
- Mouse:
pointermove stores x,y, active time; pointerleave active=false. Maybe touch events too.
- Draw HUD maybe "Move your mouse to scare the flock" and stats. But user asked simulation; overlay can be unobtrusive. Need maybe no controls.

Potential issue with canvas scaling: if ctx.setTransform(dpr,0,0,dpr,0,0), width/height CSS maybe fixed; draw in CSS pixels.

Need maybe handle high-DPI.

Need maybe use CSS style:
html, body { margin:0; width:100%; height:100%; overflow:hidden; background:#050713; }
canvas { display:block; width:100vw; height:100vh; }
.overlay { pointer-events:none; position:fixed; ... }

Need maybe include reduced motion? Not necessary.

Need maybe "full-screen" no scroll. Could use fullscreen? Browser fullscreen requires user gesture. "full-screen" likely viewport. Maybe include double-click/click to request fullscreen? Since user asks full-screen simulation. Could implement canvas click/touch toggles requestFullscreen? But maybe no external. Add overlay "Double-click to fullscreen". However maybe avoid browser full-screen API? It can run sandboxed no network. Use button? Single page. But if "full-screen" means CSS 100vh. Could include double-click to request fullscreen:
document.addEventListener('dblclick', () => { if (!document.fullscreenElement) document.documentElement.requestFullscreen?.(); else document.exitFullscreen?.(); });
But no need. Maybe user wants full-screen app. Add.

Need maybe ensure mouse flee works when pointer over canvas; pointermove on window. Use pointer events.

Need maybe use deterministic? Random.

Need maybe performance: O(n^2) 240 = 57k per frame, okay.

Need maybe avoid "network requests". No external.

Need write file.

Need maybe verify file present maybe ls.