Should Mrs Mst Nasima Akther read Mst as a title, now that its exclusion's reason doesn't hold? #1130

mst, the romanization of Bengali মোসাঃ (Mosammat, the honorific before a woman's name), is excluded in bn.toml. The recorded reason is that it "collides with real names where the native script cannot" (#343).

The reason doesn't hold. Measured 2026-11-06 with tools/name_usage.py mst:

• Names: no source lists it as a name. US Census 2010 has it under 100 surnames, US SSA under 5 births a year, and nam_dict none.
• The real collision: it's a US credential, with 113 NPPES providers credentialed MST (Master of Science in Teaching), all after the name.

What listing it as a salutation would move, measured with config_diff.py diff --local all --committed on 9cdc64bc: 145 names.

• Gains, about 140: Bangladeshi women's names that read Mst as the given name today, mostly in PSC and ORCID (Mrs Mst Nasima Akther → title Mrs Mst, given Nasima; Mst Farhana Chowdhury → given Farhana).
• Losses: the credential after a name, such as the Oxford MSt and the US MST (Steven Selchen, MD MSt FRCPC, Keith A Josephs, M.D. MST, MSc), which would read as a title.

Proposal: list mst as both a salutation and a credential, a deliberate title/suffix dual as ms and sr are, so position decides. In front it's the title; after the name it's the credential. To check: the comma cases, and whether Mst. with its period changes anything (it already reads as a title by rules/H2's shape where it opens a name).

The other two exclusions #1115 asked about hold. Measured the same way:

• bc (cs.toml, the Czech Bachelor): listing it moves 74 names. 56 Czech candidates written Bc. et Bc. Alena Mačková gain. But the initials BC and the US nursing credential (ADAMKOWSKI, BC, Elinor S. Strock, APRN, BC) would read as titles, as the exclusion says. Bc. with its period already reads as a title where it opens a name. The doubled Bc. et Bc. is Should a connective join two titles that only their period makes titles, as in Ing. et Ing. Jan Novák? #970's shape (Ing. et Ing.).
• sig (it.toml, Signor): listing it moves 25 names, 16 of them FEC given names (ANDERMAN, SIG) that would read as titles. The exclusion's reason, that Sig is a given name, stands.