Khối `render:` — vẽ trực quan (alias `plots:`)

Plot DSL trả về JSON ChartCmd; FE adapter (@/lib/candora/quantaAdapter) render trên Candora Charts. 11 plot kinds: line, band, histogram, marker, background, level, trendline, fibonacci, volume_profile, box, text.

render:
  panel main:
    line fast as "Fast" in cyan
    line slow as "Slow" in orange
    mark long_setup as "Buy" at below_bar in lime shaped arrow_up
    box [t1, p1] to [t2, p2] as "Zone" in maroon dashed with opacity 20pct
  panel "rsi" (height: 40pct):
    line rsi14 as "RSI" in amber
    level 70 as "OB" in red dashed

• Panel "main" dùng chung scale với candle.
• Panel khác ("rsi", "macd", …) tự render trên pane riêng.
• Chiều cao pane: panel "rsi" (height: 40pct): hoặc story panel "Volume" with height 20pct: — 40pct = 40% chiều cao chart; pane main nhận phần còn lại.
• Bareword enum: tên màu (cyan, green, …), shape marker CANDORA (circle, square, arrow_up, arrow_down, triangle_up, triangle_down, cross, diamond), location (above_bar, below_bar, at_price).
• line(..., dash: true) — nét đứt (ATR trail, BB band, level tham chiếu).
• fibonacci(from: [t, giá], to: [t, giá]) — neo theo giá; verb v2: `fibo [t,p] to [t,p] …`.
• box(from: [t1, y1], to: [t2, y2], …) — from = góc phải (tín hiệu), to = góc trái (lùi quá khứ).
• text(mask, "nhãn", location: below_bar) — neo giá theo location giống marker.
• Không có plot icon — dùng marker(..., text: "…") hoặc text(...) nếu cần nhãn chữ.