Felix #1 / Markus #5 / Sara #1 (PR #366 review). The naive
text.replace("@" + old, "@" + new) silently corrupted any composite mention
that began with the renamed single-name person — e.g. renaming the
single-name "Hans" turned "@Hans Müller" into "@Henry Müller", obliterating
the historical reference to Hans Müller without warning.
Replace with a regex matching "@OldName" only at a token boundary: not
followed by a letter/digit/hyphen (catches @Hans-Peter) and not followed by
"<space><uppercase>" (catches @Hans Müller). False negatives — e.g.
sentence-initial "@Hans Bekam" — are accepted as the conservative
trade-off; corruption is irrecoverable, missed renames are not.
The new failing test reproduced the reviewer scenario exactly: two persons
("Hans Müller" + single-name "Hans"), one block referencing both, rename
Hans → Henry. Pre-fix output corrupted "@Hans Müller" to "@Henry Müller";
post-fix preserves the composite mention and only updates the standalone.
The existing partial-name guard test (Hans-Peter Müller / Hans Müller) and
multiple-occurrences test still pass — the regex is a strict superset of
the boundary constraints already covered.
Refs #362#366
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>