Commit 47cdf72 shipped a pattern that matched one closing paren and emitted one,
netting an extra `)` in the Angular bundle:
c(2,"filterByProviders",["STORJ_IX","S3","B2"]))("required",!0)
^^ syntax error
The TrueNAS web UI went blank. Worse, MARKER was now present in the file, so
every later run reported "already patched" and skipped -- the patch could not
heal itself, and the bundle had to be hand-restored from the .pre-truecloud-patch
backup.
patch_ui.py now compares the parenthesis balance before and after substitution and
refuses to write if it changed. A bundle we cannot patch correctly is left exactly
as it was: an unpatched UI is a missing dropdown entry, a corrupted one is a dead
web UI.
Tests cover the real regression (verbatim 47cdf72 pattern) end to end: it still
matches, the balance still shifts, main() refuses, and the file on disk is
byte-for-byte unchanged. README documents the manual recovery for anyone who
already hit it.
93 tests, ruff and shellcheck clean.
flan
51bf5326d9