infra: CHANGE some cleanup regarding the .env process with container

build.sh

@@ -11,17 +11,28 @@ TEMPLATES_DIR="templates"
 ASSETS_DIR="assets"
 
 # Load .env if present; see .env.example for every option and its default.
-# Precedence: command line flags > environment > .env > built-in defaults.
+# Parsed as plain KEY=VALUE (not sourced), so the same file also works with
+# `podman run --env-file`. Values already in the environment are left alone,
+# which gives: flags > environment > .env > built-in defaults.
 ENV_FILE="${ENV_FILE:-.env}"
 if [[ -f "$ENV_FILE" ]]; then
-    # Remember caller-supplied values so the file cannot clobber them
-    env_override=$(export -p | grep -E '^declare -x (STRIP_EXIF|GALLERY_TITLE|SHOW_FOOTER)=' || true)
-    # shellcheck source=/dev/null
-    source "$ENV_FILE"
-    if [[ -n "$env_override" ]]; then
-        eval "$env_override"
-    fi
-    unset env_override
+    while IFS= read -r env_line || [[ -n "$env_line" ]]; do
+        env_line="${env_line%$'\r'}"                       # tolerate CRLF
+        env_line="${env_line#"${env_line%%[![:space:]]*}"}" # trim leading space
+        [[ -z "$env_line" || "$env_line" == \#* ]] && continue
+        [[ "$env_line" == *=* ]] || continue
+        env_key="${env_line%%=*}"
+        env_val="${env_line#*=}"
+        env_key="${env_key%"${env_key##*[![:space:]]}"}"    # trim trailing space
+        [[ "$env_key" =~ ^[A-Za-z_][A-Za-z0-9_]*$ ]] || continue
+        # Strip one layer of matching quotes (omit them for --env-file compatibility)
+        if [[ ${#env_val} -ge 2 && ( "$env_val" == \"*\" || "$env_val" == \'*\' ) ]]; then
+            env_val="${env_val:1:${#env_val}-2}"
+        fi
+        # Anything already set (environment, or earlier in this script) wins
+        [[ -n "${!env_key+x}" ]] || printf -v "$env_key" '%s' "$env_val"
+    done < "$ENV_FILE"
+    unset env_line env_key env_val
 fi
 
 # Image metadata (EXIF/GPS/IPTC/XMP) is stripped by default.