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

tools/steam_paths.py

@@ -0,0 +1,119 @@
+#!/usr/bin/env python3
+# ABOUT ME
+# Finds the installed Cosmoteer game data and the user Mods folder, wherever
+# Steam put them. Shared by install.sh and tests/test_mod.py.
+#
+# Why it exists: Steam lives in different places (native, Flatpak, Snap,
+# Debian package, Windows) and a game can sit in any library listed in
+# steamapps/libraryfolders.vdf, often on another disk. Hard-coded globs miss
+# those; this reads Steam's own library list instead.
+#
+# Environment overrides always win: COSMOTEER_DATA for the Data folder,
+# COSMOTEER_MODS_DIR for the Mods folder.
+#
+# Usage:  python3 tools/steam_paths.py --data   print the Data folder
+#         python3 tools/steam_paths.py --mods   print the Mods folder
+#         Exit 1 with the roots tried on stderr when nothing is found.
+
+import glob
+import os
+import re
+import sys
+
+APP_ID = "799600"
+PROTON_PROFILE = "compatdata/" + APP_ID + "/pfx/drive_c/users/steamuser/Saved Games/Cosmoteer"
+
+# Steam roots relative to HOME, in the order they are tried.
+STEAM_ROOTS_UNDER_HOME = [
+    ".local/share/Steam",
+    ".steam/steam",
+    ".steam/debian-installation",
+    ".var/app/com.valvesoftware.Steam/.local/share/Steam",
+    ".snap/steam/common/.local/share/Steam",
+    "snap/steam/common/.local/share/Steam",
+]
+
+_VDF_PATH = re.compile(r'"path"\s+"([^"]+)"')
+
+
+def steam_roots(env=None):
+    """Candidate Steam install roots for this environment (existing or not)."""
+    env = os.environ if env is None else env
+    home = env.get("HOME")
+    roots = [os.path.join(home, rel) for rel in STEAM_ROOTS_UNDER_HOME] if home else []
+    program_files = env.get("PROGRAMFILES(X86)") or env.get("ProgramFiles(x86)")
+    if program_files:
+        roots.append(os.path.join(program_files, "Steam"))
+    return roots
+
+
+def libraries(env=None):
+    """Every Steam library folder: each root plus what its libraryfolders.vdf lists."""
+    seen = []
+    for root in steam_roots(env):
+        for candidate in [root] + _vdf_libraries(root):
+            candidate = os.path.realpath(candidate)
+            if candidate not in seen and os.path.isdir(os.path.join(candidate, "steamapps")):
+                seen.append(candidate)
+    return seen
+
+
+def _vdf_libraries(root):
+    vdf = os.path.join(root, "steamapps", "libraryfolders.vdf")
+    if not os.path.isfile(vdf):
+        return []
+    with open(vdf, encoding="utf-8", errors="replace") as f:
+        return [p.replace("\\\\", "\\") for p in _VDF_PATH.findall(f.read())]
+
+
+def find_data_dir(env=None):
+    env = os.environ if env is None else env
+    override = env.get("COSMOTEER_DATA")
+    if override:
+        return override
+    for library in libraries(env):
+        data = os.path.join(library, "steamapps", "common", "Cosmoteer", "Data")
+        if os.path.isdir(data):
+            return data
+    return None
+
+
+def find_mods_dir(env=None):
+    env = os.environ if env is None else env
+    override = env.get("COSMOTEER_MODS_DIR")
+    if override:
+        return override
+    patterns = [
+        os.path.join(library, "steamapps", PROTON_PROFILE, "*", "Mods") for library in libraries(env)
+    ]
+    profile = env.get("USERPROFILE")
+    if profile:
+        patterns.append(os.path.join(profile, "Saved Games", "Cosmoteer", "*", "Mods"))
+    for pattern in patterns:
+        for match in sorted(glob.glob(pattern)):
+            if os.path.isdir(match):
+                return match
+    return None
+
+
+def main(argv):
+    if argv[1:] == ["--data"]:
+        found = find_data_dir()
+        what = "Cosmoteer Data folder"
+    elif argv[1:] == ["--mods"]:
+        found = find_mods_dir()
+        what = "Cosmoteer Mods folder"
+    else:
+        print(__doc__ or "usage: steam_paths.py --data | --mods", file=sys.stderr)
+        return 2
+    if found:
+        print(found)
+        return 0
+    print(f"Could not find the {what}. Steam roots tried:", file=sys.stderr)
+    for root in steam_roots():
+        print(f"  {root}", file=sys.stderr)
+    return 1
+
+
+if __name__ == "__main__":
+    sys.exit(main(sys.argv))