fix(android): share signing identity across all release channels

scripts/android-version-code.py

@@ -0,0 +1,33 @@
+#!/usr/bin/env python3
+"""Derive one Android version sequence for every release channel and workflow."""
+
+import argparse
+import re
+
+
+def version_code(version: str) -> int:
+    match = re.fullmatch(
+        r"(0|[1-9][0-9]*)\.(0|[1-9][0-9]*)\.(0|[1-9][0-9]*)"
+        r"(?:-(alpha|beta|rc)\.([1-9][0-9]*))?",
+        version,
+    )
+    if not match:
+        raise ValueError("Android versions must be X.Y.Z or X.Y.Z-{alpha,beta,rc}.N")
+    major, minor, patch = map(int, match.group(1, 2, 3))
+    stage, number = match.group(4, 5)
+    if major > 20 or minor > 99 or patch > 99 or (number and int(number) > 999):
+        raise ValueError("Android versions support major 0–20, minor/patch 0–99, and prerelease 1–999")
+    # Reserve 10,000 codes for each patch. This stays below Play's 2.1B limit.
+    # alpha.999 < beta.1 < rc.1 < stable < next patch's alpha.1.
+    suffix = {"alpha": 0, "beta": 1000, "rc": 2000}.get(stage, 9999)
+    return major * 100_000_000 + minor * 1_000_000 + patch * 10_000 + suffix + int(number or 0)
+
+
+if __name__ == "__main__":
+    parser = argparse.ArgumentParser(description=__doc__)
+    parser.add_argument("version")
+    args = parser.parse_args()
+    try:
+        print(version_code(args.version))
+    except ValueError as error:
+        raise SystemExit(str(error)) from error