grammar+db: 3i — auto_column_overridden diagnostic (ADR-0033 §8.2)

New dml_auto_column_diagnostics pass: a WARNING when a SQL INSERT's
explicit column list names a serial/shortid (auto-generated) column —
the explicit value bypasses the auto-counter/generator and may collide
with later auto-generated values. Advisory only (ADR-0027 §1); the
statement still runs. Conflict-target columns (distinct
conflict_target_column role) are not mistaken for inserted columns.

Catalog key diagnostic.auto_column_overridden (engine-neutral).
Tests (+4): serial + shortid fire; omitted is silent; ON CONFLICT
target not falsely flagged. 1580 pass / 0 fail / 1 ignored. Clippy
clean. Remaining 3i: insert_arity_mismatch, not_null_missing (needs
TableColumn not_null+default), cross-cut verification, #12 UPSERT
DO UPDATE validation.

src/friendly/strings/en-US.yaml

@@ -501,6 +501,8 @@ diagnostic:
   cte_arity_mismatch: "CTE `{cte}` declares {declared} columns but its body has {actual}"
   compound_arity_mismatch: "`{op}` requires both sides to have the same number of columns — left has {left_n}, right has {right_n}"
   duplicate_cte: "duplicate `WITH` table name: `{name}`"
+  # ADR-0033 §8 — Phase-3 DML diagnostic keys.
+  auto_column_overridden: "column `{column}` is auto-generated (`{type}`); providing an explicit value bypasses the auto-counter and may collide with later auto-generated values"
 
 # Engine-error translations: an engine-rejected SQL statement
 # reaches the friendly-error layer (ADR-0019) and these keys