Alternative to the quote-aware string fix: represent committed To/Cc/Bcc
recipients as Recipient[] ({name?, email}) with a separate input-text
string per field, instead of a single comma-joined string parsed with
split(','). Structured recipients can never be torn apart on a delimiter,
so a display name containing a comma ("Doo, John <john@doo.org>", as
produced on Reply-All) stays a single chip.
- email-composer-utils: add Recipient type, parseRecipient/formatRecipient,
and parseRecipientList/formatRecipientList for the (de)serialization
boundary (ComposerDraftData stays a string; quoting keeps it lossless).
Remove the now-unused string-chip helpers.
- email-composer: to/cc/bcc are Recipient[]; toInput/ccInput/bccInput hold
the in-progress text. Reply/forward init, autocomplete, chip edit, drag &
drop (payload now carries the structured recipient), send/draft/validation
and template paths all operate on arrays. withInput() folds uncommitted
typed text into the send/validation set.
- Tests updated for the array contract; add comma-in-name chip coverage.
