Add bitmap font, UI primitives and a HUD with message log

Ports the CP437 font renderer from wds to the framebuffer: proportional
advance from measured ink bounds, luminance-keyed mask, word wrap. The
right 80 px strip becomes a HUD with name, HP bar, population and a log
fed from sim events; Attacked/Died now carry the type ids the log needs,
since the victim is gone from the world by the time events are read.

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

notes/04-text_renderer.md

@@ -2,29 +2,20 @@
 
 ## Current state
 
-No text rendering exists yet. No font loading or glyph blitting code exists.
+`game/src/font.rs` — a CP437 bitmap font ported from the `wds` project.
 
-## Goal
-
-Draw ASCII text into the RGB565 framebuffer using a bitmap font.
-
-## Design notes
-
-- A bitmap font is the right fit: each glyph is a small masked tile, blitted
-  directly into the framebuffer using the existing blit primitive in `pixelhelper.rs`.
-- Likely approach: a fixed 8×8 or similar glyph grid packed into a PNG,
-  one glyph per ASCII codepoint starting at 0x20 (space).
-- The font image only needs its alpha mask: glyph pixels are opaque, background transparent;
-  the caller supplies the color and `draw_text` paints the mask with it.
-- API sketch:
-  ```rust
-  fn draw_text(frame: &mut [u16], font: &Font, x: i32, y: i32, color: u16, text: &str);
-  ```
-- `Font` holds the glyph sheet as an `Image` plus glyph width/height.
+- Atlas: 32 columns × 8 rows of fixed cells, codepoint = index (`A` at 65 → column 1,
+  row 2). Loaded with `Image::from_png`; the mask is derived from luminance (white on
+  black), so the caller paints glyphs in any RGB565 color.
+- Proportional advance: on load the ink span of every glyph (leftmost/rightmost lit
+  column) is measured. `draw` crops to that span and advances by ink width + 1 px
+  tracking; blank glyphs (space) advance half a cell.
+- `cp437(char)` maps ASCII 1:1 and the accented letters the atlas has (ä ö ü ß …);
+  everything else becomes `?`.
+- `text_width` and `wrap` (word wrap with hard `\n`) for layout.
+- Font in use: `assets/fonts/cga-8x8.png` (Oldschool PC Font Pack, CGA 8×8).
 
 ## Open questions
 
-- How do we handle proportional spacing of different characters?
-- How do we store font data in memory?
-- How do we handle font color rendering?
-- How do we handle special characters like Ä, Ö, Ü, ß, etc.?
+- A second, smaller or larger font (the EGA 8×14 from `wds`) once the UI needs hierarchy.
+- Text color per span / inline markup for the log — not before it is needed.