walker: flag LIKE on a numeric column (ADR-0027 Amendment 1)

LIKE is a text-pattern match; against a numeric column (int,
real, decimal, serial) it runs but is almost never intended.
predicate_warnings now emits a WARNING for it, spanned at the
target column. New Type::is_numeric; catalog key
diagnostic.like_numeric; ADR-0027 gains "Amendment 1" and the
adr/README index line is updated per the index-upkeep rule.

bool and the text-/blob-backed types are deliberately not
flagged — see the amendment for the rationale.

3 walker tests (int, decimal NOT LIKE, text-column clean).
1108 passing, clippy clean.

docs/adr/0027-input-validity-indicator.md

@@ -39,7 +39,8 @@ runs if submitted).
 - **WARNING** — the input is valid and *will* run, but is
   very likely not what a knowledgeable user wants: a
   type-mismatched comparison, or `= NULL` (both from
-  ADR-0026 §7).
+  ADR-0026 §7). Amendment 1 adds a third trigger — `LIKE`
+  against a numeric column.
 
 The split is *certainty of failure* versus *likely
 misleading*. The indicator shows the highest severity
@@ -289,6 +290,44 @@ choices and deviations from the sketch above:
   `input_verdict` has a parse-outcome / schema-existence /
   expression-warning / existing-cases-sweep test set.
 
+## Amendment 1 — `LIKE` on a numeric column (2026-05-19)
+
+§1 defined the WARNING set as exactly a type-mismatched
+comparison and `= NULL`. A third trigger is added:
+
+- **`LIKE` against a numeric column.** `LIKE` is a
+  text-pattern match — `%` / `_` wildcards over characters.
+  Applied to a column of a numeric type (`int`, `real`,
+  `decimal`, `serial`) it still runs — the engine matches the
+  pattern against the value's text form — but is almost never
+  what the user wants; they most likely mean a comparison or
+  `BETWEEN`. It is a WARNING, consistent with the advisory
+  posture (§5): the command still submits. The negation is
+  irrelevant — `NOT LIKE` on a numeric column is just as
+  dubious.
+
+Scope is deliberately narrow — only *numeric* target columns
+are flagged:
+
+- `bool` is integer-backed (0/1) but excluded; the handoff
+  item this implements named numeric columns specifically.
+- The text-backed types (`text`, `shortid`, `date`,
+  `datetime`) are not flagged: `LIKE 'A%'` on text is its
+  intended use, and a prefix match on an ISO `date` /
+  `datetime` string is genuinely useful.
+- `blob` is left unflagged.
+
+Widening to those types is a future model extension if a need
+appears.
+
+This is exactly the kind of "we can tell, before it runs,
+that this is dubious" case §6 anticipated: the trigger plugs
+into the existing model rather than being a one-off check. It
+lives alongside the others in `walker::predicate_warnings`
+(the `Predicate::Like` arm, via `like_numeric_warning`); the
+target column operand's span drives the highlight; the
+message key is `diagnostic.like_numeric`.
+
 ## See also
 
 - ADR-0003 — input modes; the input field and its mode