stdlib: pub-mark sweep for io/math/option/result/testing (follow-up to #505)

[hyperpolymath]

What

PR #505 closed the pub-visibility gap in stdlib/string.affine (18 fns made pub) and stdlib/collections.affine (22 fns made pub). The same gap exists in 5 other stdlib modules — they have /// doc-comment public-API intent but missing pub keywords.

Inventory (counted 2026-05-31)

Module	pub fns	private fns (likely-meant-to-be-pub)
stdlib/io.affine	0	15
stdlib/math.affine	0	36
stdlib/option.affine	1	35
stdlib/result.affine	0	24
stdlib/testing.affine	0	26

Total: 136 likely-pub-intent fns currently unreachable from consumers.

Why

Same root cause as #505: /// doc-comment convention was applied broadly when the modules were first written, but the pub keyword from ADR-011 wasn't retroactively added to every doc-commented fn. Discovered while porting migration/shared/PortNames.affine in idaptik (standards#279) — string::starts_with was the first surfaced casualty.

Scope

Per module: add pub to every fn whose body has a /// doc comment. Leave module-private helpers (those that don't have ///) alone. Cross-check with each module's consumer surface — anything called by option from result, etc., needs reachability.

Per-module gates likely needed:

• option.affine — many fns depend on each other; need topological pub order.
• math.affine — likely all 36 are pub-intent (pure math fns).
• testing.affine — 26 fns; these are the assertion DSL consumers use.
• io.affine + result.affine — straightforward.

Test plan

• dune runtest 354/354 pass after each module edit
• Smoke: write one consumer file per module that uses a representative fn and runs check
• Once landed, idaptik migration/shared/ + panll migration/modules/ can use more stdlib surface without local re-impl

Estate impact

Unblocks future ports in the standards#252 ReScript→AffineScript campaign and the standards#254 JS→AffineScript campaign — both have STEP-4 bindings dependencies (#446 umbrella). Each port that currently hand-rolls a stdlib equivalent (because it can't reach the canonical one) accumulates drift; closing the pub gap eliminates the local-helper pattern as a default.

Refs

• affinescript#505 — the precedent (string + collections)
• standards#279 — STEP 8 megaport that surfaced this
• standards#252 — campaign UMBRELLA
• affinescript#446 — top-50 framework bindings UMBRELLA