feat: v4.1.0 -- workshop-ready (logo, path discovery, docs)

Players install from Steam Workshop instead of install.sh, which failed on
Windows (bash) and a Manjaro box (hard-coded Mods globs). Adds Logo +
logo.png the uploader ships, tools/steam_paths.py reading Steam's
libraryfolders.vdf (Flatpak/Snap/second disk/Windows), and README install
tiers plus in-game publishing steps.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_014TkQMhvEyoFqKzeCC69N6o

tests/test_mod.py

@@ -8,23 +8,20 @@
 # against the player's actual installed game data, before the game is launched.
 #
 # Run: python3 tests/test_mod.py
-# The game install is found automatically, or set COSMOTEER_DATA to override.
+# The game install is found through Steam's own library list (tools/steam_paths.py),
+# or set COSMOTEER_DATA to override.
 
 import os
 import re
 import sys
 
+MOD_ROOT = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
 sys.path.insert(0, os.path.dirname(os.path.abspath(__file__)))
+sys.path.insert(0, os.path.join(MOD_ROOT, "tools"))
 
 import rules_parser
+import steam_paths
 
-MOD_ROOT = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
-
-CANDIDATE_DATA_DIRS = [
-    "/mnt/SSD4TB/SteamLibrary/steamapps/common/Cosmoteer/Data",
-    os.path.expanduser("~/.local/share/Steam/steamapps/common/Cosmoteer/Data"),
-    os.path.expanduser("~/.steam/steam/steamapps/common/Cosmoteer/Data"),
-]
 
 # Component fields whose value names another component in the same part.
 COMPONENT_REF_FIELDS = {
@@ -56,13 +53,8 @@ def check(condition, message):
 
 
 def find_data_dir():
-    override = os.environ.get("COSMOTEER_DATA")
-    if override:
-        return override
-    for path in CANDIDATE_DATA_DIRS:
-        if os.path.isdir(path):
-            return path
-    return None
+    """Locate the installed game's Data folder via tools/steam_paths.py."""
+    return steam_paths.find_data_dir()
 
 
 DATA = find_data_dir()
@@ -745,6 +737,24 @@ def test_manifest_is_well_formed():
     )
 
 
+def test_manifest_declares_existing_logo():
+    """Steam Workshop shows the mod's Logo; the file must ship inside the mod
+    folder, be a real PNG, and stay under Steam's 500 KB preview limit."""
+    mod = rules_parser.parse_file(os.path.join(MOD_ROOT, "mod.rules"))
+    logo = mod.get("Logo")
+    check(logo is not None, "mod.rules is missing the 'Logo' field")
+    if logo is None:
+        return
+    path = os.path.join(MOD_ROOT, logo.value.strip('"'))
+    check(os.path.isfile(path), f"Logo file does not exist: {path}")
+    if not os.path.isfile(path):
+        return
+    with open(path, "rb") as f:
+        magic = f.read(8)
+    check(magic == b"\x89PNG\r\n\x1a\n", f"Logo is not a PNG: {path}")
+    check(os.path.getsize(path) < 500_000, "Logo must be under 500 KB for Workshop upload")
+
+
 def main():
     if DATA is None or not os.path.isdir(DATA):
         print("SKIP: Cosmoteer Data folder not found. Set COSMOTEER_DATA to run these tests.")