docs(adr): record evidence rules for canonical slot validation

[e54-bot]

Refs #283 (records the decision; the opy-rs probe-gap acceptance item remains).

Decision

ADR-0014 keeps a single canonical validation contract owned by workshop-rs:

• Structural failures (identity, arity, enum domain, reference category) are always rejected.
• A declared-type mismatch is a presumption that yields to acceptance evidence; a rejection stricter than the declared type needs rejection evidence.
• Evidence classes and scope: client-exported real-project text; deliberate upstream emission rules (optimizer substitutions, First Of wrapping), scoped to the parameter or type the rule is keyed on; upstream reports of client behavior; declared types as presumption only. Upstream pass-through, loose any, and runtime equivalence are not evidence. A live-client capture overrides the rest when available.

Applied to the #283 families:

1. Boolean parameters accept any value (typed rule; OverPy chore: release v0.3.5 #182 and its type-keyed First Of rule).
2. Arrays in the five Object text parameters stay rejected; opy-rs records an approved exception.
3. Number 0 in the createEffect position stays rejected; opy-rs records an approved exception.

core-boundaries.md gains a short validation-acceptance section that routes to the ADR.

Follow-up

• workshop-rs: implement the Boolean parameter rule with regressions; add per-parameter coercions evidenced by reference optimizeForSize substitutions (e.g. createDummy).
• opy-rs: First Of wrapping observed from the pinned reference; approved exceptions for families 2 and 3 with pinning tests.

Verification

Docs-only. git diff --check clean; relative links resolve. Upstream citations are pinned to OverPy 1e26889 (9.7.10) and OSTW dde3da1.