cleanup: QOL improvements — gitignore, Tags constants, remove debug artifacts

- Add .DS_Store, unused/, .vscode/settings.json to .gitignore
- Add .editorconfig (tabs for Lua, LF, UTF-8)
- Fix duplicate submodule entry in .gitmodules
- Add Tags table (player, tank, ground, granade, ammoCrate) — replace magic numbers
- Add SCREEN_W/SCREEN_H constants
- Fix leaked global variable `c` in Game.lua
- Remove Noble.showFPS = true from BomberScene
- Remove debug print() calls from granade, enemy, BomberScene
- Fix clean_build_dir glob bug in both build scripts
- Make PLAYDATE_SDK_PATH configurable via env var

source/scripts/tankSprite.lua

@@ -10,7 +10,7 @@ function Tank:init(x, y, ground)
 
     -- Collision properties
     self:setZIndex(ZIndex.enemy)
-    self:setTag(2)
+    self:setTag(Tags.tank)
     self:setCollideRect(4, 56, 147, 65)
     self:setGroups(CollideGroups.enemy)
     self:setCollidesWithGroups(