* DrawHelper
  A utility class for safe and bounded terminal drawing using a local coordinate system.
  Supports sub-regions, colors, and drawing of text, boxes, and lines.

** Constructor
  #+BEGIN_SRC python
  DrawHelper(screen, x: int, y: int, width: int, height: int)
  #+END_SRC
  - `screen`: curses window to draw on.
  - `x`, `y`: Top-left corner of the region in parent coordinates.
  - `width`, `height`: Size of the drawing region.

** Color
  - `set_color(color_pair: int)`
    Set the active color pair for subsequent drawing.

** Drawing Primitives
  - `put_char(x: int, y: int, char: str, attrs=0)`
    Draw a single character at `(x, y)` within bounds.

  - `put_string(x: int, y: int, text: str, attrs=0)`
    Draw a string at `(x, y)`, clamped to fit the width.

  - `draw_line(x: int, y: int, length: int, char: str,
               horizontal=True, attrs=0, ender=None)`
    Draw a horizontal or vertical line using the given character.
    Optional `ender` is placed at both ends.

  - `filled_rectangle(x: int, y: int, width: int, height: int, char: str = ' ')`
    Draw a filled rectangle using the given character.

  - `rectangle(x: int, y: int, width: int, height: int)`
    Draw an outlined rectangle using Unicode box-drawing characters.

** Text Utilities
  - `multiline_text(x: int, y: int, text: str) -> int`
    Render multiline text starting at `(x, y)`.
    Returns the number of lines drawn.

  - `header_line(y: int, text: str, char: str = '─', attrs=0)`
    Draw a horizontal line with centered `text` at row `y`.

  - `info_line(row: int, start: int, end: int,
               strings: List[str], margin=1, attrs=0)`
    Display a pipe-separated list of `strings` between `start` and `end` at `row`.

** Region Management
  - `sub_region(x: int, y: int, width: int, height: int)`
    Context manager that yields a nested `DrawHelper` with its own local coordinates.

    #+BEGIN_SRC python
    with helper.sub_region(x, y, w, h) as sub:
        sub.put_string(0, 0, "Inside sub-region")
    #+END_SRC

** Notes
  - Coordinates are relative to the helper’s own region.
  - Drawing outside bounds is silently ignored.
  - Drawing operations use safe wrappers to suppress `curses.error`.