Remove Python dependency from secret decrypt

.forgejo/actions/decrypt-release-secrets/action.yml

@@ -191,9 +191,20 @@ runs:
           } >> "$GITHUB_ENV"
         }
 
+        decode_base64_stream() {
+          if command -v base64 >/dev/null 2>&1; then
+            base64 -d 2>/dev/null || base64 -D
+          elif command -v openssl >/dev/null 2>&1; then
+            openssl base64 -d -A
+          else
+            echo "::error ::base64 or openssl is required to decode release secrets." >&2
+            return 127
+          fi
+        }
+
         decode_base64_to_file() {
           local output="$1"
-          python3 -c 'import base64, pathlib, sys; pathlib.Path(sys.argv[1]).write_bytes(base64.b64decode(sys.stdin.buffer.read()))' "$output"
+          decode_base64_stream > "$output"
         }
 
         decrypt_appstore_connect() {
@@ -259,7 +270,7 @@ runs:
           cert_base64="${APPLE_SIGNING_CERTIFICATE_BASE64:-${APPLE_DISTRIBUTION_CERTIFICATE_BASE64:-}}"
           cert_password="${APPLE_SIGNING_CERTIFICATE_PASSWORD:-${APPLE_DISTRIBUTION_CERTIFICATE_PASSWORD:-}}"
           if [[ -z "$cert_password" && -n "${APPLE_SIGNING_CERTIFICATE_PASSWORD_BASE64:-}" ]]; then
-            cert_password="$(printf '%s' "$APPLE_SIGNING_CERTIFICATE_PASSWORD_BASE64" | python3 -c 'import base64,sys; print(base64.b64decode(sys.stdin.buffer.read()).decode(), end="")')"
+            cert_password="$(printf '%s' "$APPLE_SIGNING_CERTIFICATE_PASSWORD_BASE64" | decode_base64_stream)"
           fi
           if [[ -z "$cert_base64" || -z "$cert_password" ]]; then
             echo "::error ::${file} must define APPLE_SIGNING_CERTIFICATE_BASE64 and APPLE_SIGNING_CERTIFICATE_PASSWORD." >&2

evolution/proposals/BEP-0009-release-infrastructure-and-store-upload-pipeline.md

@@ -79,7 +79,8 @@ The same change also makes the forge itself the release authority: release tags
   bootstrap step. Linux Namespace signing jobs install Nix at runtime, so the
   bootstrap writes Nix profile directories to `GITHUB_PATH`, the decrypt action
   resolves Nix from those profile paths, and the action builds `.#age` before
-  falling back to `.#agenix`.
+  falling back to `.#agenix`. The decrypt step must not require Python before
+  the Nix CI shell is active.
 - Produce unsigned Apple validation artifacts when signing is absent, but require signing for an App Store requested iOS release and for a Sparkle tester release. Uploadable artifacts are produced only after provisioning profiles can be synced from App Store Connect credentials and the relevant Apple certificate is proven to match the selected Google KMS key.
 - Resolve release credentials through age/agenix before signed Apple lanes run. Forgejo secrets should carry only the runner age identity fallback and the Authentik WIF client secret until OpenBao can mint the runner token directly. App Store Connect keys and signing certificates live as sealed files under `secrets/`.
 - Persist the forge runner SSH key as `/var/lib/forgejo-runner-agent/age_keystore` and export `BURROW_RUNNER_AGE_IDENTITY_PATH` so jobs can resolve agenix identities without embedding long-lived material in every workflow.