feat(types): add treemap for part-of-whole by area (#87)

Add Treemap as the 28th visual type with light, dark, and editorial variants; area, label, and information-marker verification; synchronized documentation and manifests; and plugin version 2.5.0.

docs/adr/0002-semantic-patterns-do-not-expand-the-taxonomy.md

@@ -12,6 +12,12 @@ Behavior is a separate axis. The seven semantic patterns in `references/semantic
 
 ## Consequences
 
-- "27 visual types" is a stable, verifiable claim (`verify-semantic-motion.py` and `verify-docs-sync.py` both count it).
+- The visual-type count is a stable, verifiable claim (`verify-semantic-motion.py` and `verify-docs-sync.py` both count it) — 27 when this record was accepted; see Amendments for the current figure.
 - A new behavior costs one pattern section plus a routing-table row — not a new type reference, template set, and example triple.
 - If a pattern ever needs a layout no existing type provides, that is the signal to add a type, with the full §10 shipping set.
+
+## Amendments
+
+**2026-08-18 — the count is 28.** Treemap was admitted under the escape clause above: recursive area subdivision is a layout grammar no existing type provides (bar encodes with length, nested with containment and no quantity, pyramid with rank). It shipped the full §10 set, and the counters named above moved 27 → 28 together with the prose.
+
+The decision itself is unchanged — semantic patterns still never add a type, and the count still moves only for a new *layout* grammar. What this amendment records is the procedure: the two counters are this ADR's enforcement, so a PR that edits them without amending this file has quietly made itself the authority. Amend here in the same PR, or the number in the test is just whatever the last contributor typed.