Should Smith, John PhD I, Jr. keep I as a middle initial, as Smith, John V, Jr. does? #819

rules/C9 (a one-character suffix word inside a comma part) says a single letter ending the given part stays a middle initial "where a further comma has already named the suffix (C2) … whether a name word or another suffix word stands before it." The second half no longer holds. Behind a credential, the letter joins the credential run even when a further comma follows.

PR #817's review measured that these read middle 'I' and 'I.' before #602. #602 (decisions/S8, the credential run's start) let an unambiguous credential start a run that takes a following letter.

Proposal, in rule shape

When: a one-letter suffix word ends the given part after a family comma, behind a credential, and a further comma follows, as in "Smith, John PhD I, Jr.".

Then, one of:

• (A) The rule is right. The further comma closes the generation slot, so the letter is a middle initial wherever it stands, and Should a name word after a credential join the suffix? John Smith PhD Jones reads middle Smith PhD #602's run stops before a lone letter that ends the given part ahead of a further comma.
• (B) The parser is right. Behind a credential the letter describes the credential (PSM I), and a further comma doesn't change that. C9's clause narrows to "a name word before it".

Because: under (A), a further comma naming the generation leaves no generation for the letter to be. Under (B), the rule's own first branch already says a letter behind a suffix describes that suffix, "an initial being no shape anyone writes there".

Boundaries that stay as they are: Smith, John V, Jr. → middle 'V'; Smith, PSM I → suffix 'PSM I'; Smith, John V → suffix 'V'.

Open questions

1. A or B?
2. Under (A), should the suffix-or-name report go away?
3. Under (B), C9's Accepted bullet relies on the v1 test test_roman_numeral_i_with_explicit_suffix_comma_stays_a_middle_initial. Does that test still pin the name-word half alone?

decisions/C9's Open: line should point here.