fix flatpak build: add checksums and update to GNOME 49

- Generate cargo checksum files for vendored sources
- Add checksums.json for build-time checksum creation
- Update runtime to GNOME 49 for Rust 1.93+ support
- Fix archive-type to tar-gzip for flatpak-builder

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

build-aux/flatpak-cargo-generator.py

@@ -3,7 +3,7 @@
 
 Usage:
     python3 build-aux/flatpak-cargo-generator.py [Cargo.lock] \
-        > build-aux/cargo-sources.json
+        -o build-aux/cargo-sources.json
 """
 
 import json
@@ -23,12 +23,25 @@ REGISTRY_SOURCE = "registry+https://github.com/rust-lang/crates.io-index"
 
 
 def main() -> None:
-    lockfile = sys.argv[1] if len(sys.argv) > 1 else "Cargo.lock"
+    # Parse arguments
+    lockfile = "Cargo.lock"
+    output_file = None
+
+    args = sys.argv[1:]
+    i = 0
+    while i < len(args):
+        if args[i] == "-o" and i + 1 < len(args):
+            output_file = args[i + 1]
+            i += 2
+        else:
+            lockfile = args[i]
+            i += 1
 
     with open(lockfile, "rb") as f:
         lock = tomllib.load(f)
 
     sources = []
+    checksums = {}
 
     for pkg in lock.get("package", []):
         name = pkg["name"]
@@ -38,17 +51,30 @@ def main() -> None:
 
         # Only vendor packages from crates.io (they have a checksum)
         if source == REGISTRY_SOURCE and checksum:
+            dest = f"cargo-vendor/{name}-{version}"
             sources.append(
                 {
                     "type": "archive",
-                    "archive-type": "tar-gz",
+                    "archive-type": "tar-gzip",
                     "url": f"{CRATES_IO_DL}/{name}/{version}/download",
                     "sha256": checksum,
-                    "dest": f"cargo-vendor/{name}-{version}",
+                    "dest": dest,
                 }
             )
+            checksums[f"{name}-{version}"] = checksum
 
-    print(json.dumps(sources, indent=2))
+    output = json.dumps(sources, indent=2)
+
+    if output_file:
+        with open(output_file, "w") as f:
+            f.write(output)
+        # Also write checksums file
+        checksums_file = output_file.replace(".json", "-checksums.json")
+        with open(checksums_file, "w") as f:
+            json.dump(checksums, f)
+        print(f"Generated {output_file} and {checksums_file}")
+    else:
+        print(output)
 
 
 if __name__ == "__main__":