startnet editor: harden _split_lines against doubled CRLF (\r\r\n)

A CRLF file re-CRLF'd (e.g. sed adding \r to already-CRLF lines) yields \r\r\n; the old _split_lines left a stray \r that split into a blank line between every line, so parse_boot_menu/settings/lint saw a garbled file and returned nothing. Now collapse any run of CR before a newline. Also re-deployed a clean-CRLF startnet.cmd into the live boot.wim (the earlier sed-based deploys had doubled the CR).

webapp/services/wim.py

@@ -125,7 +125,9 @@ def _split_lines(content):
     Rejoining with eol.join(...) reproduces a trailing newline because a
     trailing terminator yields a final empty element.
     """
-    return content.replace("\r\n", "\n").replace("\r", "\n").split("\n")
+    # Collapse any run of CRs before a newline (handles CRLF and a doubled
+    # \r\r\n that a bad CRLF-conversion can leave behind), then lone CR.
+    return re.sub(r"\r+\n", "\n", content).replace("\r", "\n").split("\n")
 
 
 # --- Shared regexes ---------------------------------------------------------