docs: ADR-0036 revised to surgical "validate-and-retain"; +X4/X5 open questions

Narrow ADR-0036 from "bind literals via the DSL path" to "validate literal
values (shared validators) + retain them; execute verbatim, keep auto-fill
and command identity mode-specific" — after a concrete auto-fill difference
(non-PK serial) confirmed the modes aren't identical even for single-row
literals. Augments (no longer supersedes) ADR-0030 §4 / ADR-0033 §10;
Amendment 3 stands. README + forward-notes on 0030/0033 updated. Records
requirements.md X4 (serial auto-fill — possible bug) and X5 (framework
cohesion / share-mechanics-not-commands).

docs/adr/0030-advanced-mode-sql-surface.md

@@ -157,17 +157,18 @@ that `docs/simple-mode-limitations.md` records as the inverse
 of the simple-mode subset. The DSL `Expr` is the *DSL's*
 representation; the SQL surface does not round-trip through it.
 
-> **Forward note (2026-05-26).** The **Proposed ADR-0036** narrows the
-> "DML → validated SQL text" half of this section: **literal data
-> values** in `INSERT`/`UPDATE` should be parsed to typed `Value`s,
-> validated, and bound as parameters (as the DSL already does), not
-> handed to the engine as text — so advanced mode gets the same
-> value-validation, hinting, highlighting, and error context as simple
-> mode. The `SELECT` half and the full-expression-surface rationale above
-> **stand**: expressions and queries remain verbatim text (ADR-0026's
-> limited `Expr` is *not* imposed on the SQL surface). The dividing line
-> is "bindable literal vs engine-evaluated expression-or-query." Pending
-> acceptance.
+> **Forward note (2026-05-26, ADR-0036 Accepted).** ADR-0036 **augments**
+> the "DML → validated SQL text" half of this section — it does **not**
+> change the execution model. Advanced-mode DML still executes verbatim;
+> what's added is that "validated" now also means *value*-validated: the
+> **literal data values** in `INSERT`/`UPDATE` are checked against the
+> playground type system (and retained for error reporting) **before** the
+> verbatim statement runs, sharing the DSL's per-type validators. No
+> binding, no reconstruction, no command-identity change (ADR-0033 Am3
+> stands). The `SELECT` half and the full-expression-surface rationale
+> above **stand**: expressions and queries remain verbatim text (ADR-0026's
+> limited `Expr` is *not* imposed on SQL). Dividing line: a static literal
+> value (validate it) vs an engine-evaluated expression-or-query.
 
 ### 5. Type vocabulary — the playground's, not the engine's