chore: refactor release workflow for modular distro and upstream builds

scripts/enable-apt-source-repos.sh

@@ -0,0 +1,53 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+enable_deb822_sources() {
+    local file="$1"
+    local tmp
+
+    tmp="$(mktemp)"
+    awk '
+        /^Types:/ {
+            if ($0 !~ /(^|[[:space:]])deb-src($|[[:space:]])/) {
+                print $0 " deb-src"
+                next
+            }
+        }
+        { print }
+    ' "$file" > "$tmp"
+    cat "$tmp" > "$file"
+    rm -f "$tmp"
+}
+
+enable_legacy_sources() {
+    local file="$1"
+    local output="$2"
+
+    awk '
+        /^[[:space:]]*deb[[:space:]]/ {
+            line = $0
+            sub(/^[[:space:]]*deb[[:space:]]+/, "deb-src ", line)
+            print line
+        }
+    ' "$file" > "$output"
+}
+
+found_sources=0
+
+for sources_file in /etc/apt/sources.list.d/*.sources; do
+    if [[ -f "$sources_file" ]]; then
+        found_sources=1
+        enable_deb822_sources "$sources_file"
+    fi
+done
+
+if [[ -f /etc/apt/sources.list ]]; then
+    found_sources=1
+    enable_legacy_sources /etc/apt/sources.list \
+        /etc/apt/sources.list.d/codex-deb-src.list
+fi
+
+if [[ "$found_sources" -eq 0 ]]; then
+    echo "No apt source list files were found under /etc/apt" >&2
+    exit 1
+fi