Add one HP per second regeneration and Half-Life starfield sky

docs/HEALTH-SKY.md

@@ -0,0 +1,34 @@
+# Health regeneration and starry sky
+
+- Living players recover exactly one HP per elapsed gameplay second, including combat.
+  Maximum is 100 HP; no healing or resurrection after death. Physics time accumulator
+  handles frame-rate variation; time at full HP does not bank healing.
+- `scripts/main.gd` uses a `PanoramaSkyMaterial` as the environment background.
+  Ambient light remains the existing constant color; sky reflections are disabled.
+- Compared local Half-Life skies `night`, `space`, and several `neb*` sets. `space`
+  was selected for a plain star field (`night` is cloudy; nebulae are colorful).
+- `assets/textures/sky/space_panorama.png`: 2048x1024 equirectangular conversion of
+  the six Valve `space*.tga` faces, not a newly generated texture. The original faces
+  are low resolution, so stars retain their original soft appearance. Source hashes
+  are in `source_manifest.json`; original Steam files are never modified.
+
+Reproduce (Pillow and FFmpeg with v360 required):
+
+```sh
+python3 tools/prepare_sky.py /path/to/Half-Life/valve/gfx/env
+```
+
+Verify with installed Godot 4.7.1:
+
+```sh
+"$G" --headless --path . --script res://tools/test_health_sky.gd
+"$G" --display-driver x11 --rendering-method gl_compatibility --path . \
+  --script res://tools/test_health_sky.gd -- --screenshot
+```
+
+Screenshot: `/tmp/zombie-star-window.png`. Test checks discrete timing, maximum,
+no healing after death, panorama dimensions, and unchanged ambient light. Existing
+music, grenade, wave, death, damage, and touch tests also pass. The existing resource
+leak/in-use warnings at test shutdown remain; they are not fixed by this change.
+
+Sky format reference: https://docs.godotengine.org/en/stable/classes/class_panoramaskymaterial.html

docs/WEB-DEPLOY.md

@@ -1,5 +1,17 @@
 # Web build and compressed deployment
 
+## Health + starry sky release: 31564f79b9f5e299
+
+See `docs/HEALTH-SKY.md`: +1 HP/second while alive, capped at 100; Half-Life
+`space` panorama visible outside windows. PCK 3,938,672 bytes; gzip payload total
+12,395,646 bytes. Previous releases retained; root backup `index-before-health-sky.html`.
+
+Build encountered an import-thread crash (`propagate_notification` off caller thread,
+signal 11). Workaround applied only to generated staging `project.godot`:
+`[editor] import/use_multiple_threads=false`; serial re-import and export succeeded.
+Upstream similar issue: https://github.com/godotengine/godot/issues/96242
+
+
 URL: https://enne2.net/pub/zombie-fps/
 Server: debian@enne2.net (bastion).
 Web root: /home/debian/public_html/zombie-fps/.