#3798 data_writer_property_test: a secret holding a newline and a literal backslash-n escapes the persisted-content property (seed 1648929202)

The property test createResourceWriter: persisted content keeps vault references exact and leaks no registered secret outside them (src/domain/models/data_writer_property_test.ts) fails deterministically with fast-check seed 1648929202 and path [IP-1]. Counterexample: nameSecret AAA, secrets [a quote-colon-quote string, and a string of newline, backslash, n, comma], jsonSecret {a: A}, extra [], note empty. The persisted text after splitting out the two references still contains a piece the redactor changes: the unescaped array holds the second secret written back with its escape sequence as characters, and the redactor's JSON-escaped form of the registered secret matches the persisted text. The code under test (data_writer.ts, secret_redactor.ts) was last changed by swamp-club#3754; the test surfaced on a verify-build run for swamp-club#3733 whose branch does not touch those files, and twelve local runs with random seeds pass, so this is a latent counterexample rather than a regression from that branch. To reproduce, pass the seed and path to fc.assert in that test. Decide whether the writer must redact the unescaped form of a registered secret whose text holds a literal backslash-n, or whether the test's unescaped case over-approximates what the redactor promises.