record tags as built: ADR-0032

The queue said to re-adopt the taxonomy decision when tags landed and I did not,
so ideas/deferred-decisions.md claimed no tag pages existed while /tags/ had been
serving for two commits. ADR-0032 records what the code actually does; only the
feed half stays deferred, and it lands with declared types since feed membership is
part of a type declaration.

Folded from a separate state commit:
state: bump verified-against; narrow the declared-types trigger

Sequences do not need a type declaration — membership and ordering come from
frontmatter — so the trigger for declared types is feeds or check, whichever lands
first.

docs/decisions.md

@@ -367,3 +367,20 @@ Consequence: cheap — the guard cannot be forgotten, and the test is one symlin
 go through the root handle, so no helper may take a `string` path and open it directly, and the root is
 held for the life of the process.
 Revisit if: never. A hand-rolled cleaner is strictly worse.
+
+## ADR-0032 — Tags: one global namespace, grouped in the listing
+Date: 2026-07-30 · Status: accepted (the tag half of withdrawn ADR-0018, now built; the feed half is still
+deferred in `ideas/deferred-decisions.md`)
+Decision: `tags` is one global namespace across every section. `/tags/{term}/` lists everything carrying a
+term, `/{section}/tags/{term}/` narrows it, and listings group by section. The URL form of a term is
+lowercased with whitespace hyphenated, preserving script, so case is not a distinction and Bengali passes
+through unchanged. Structural metadata with a fixed term set — `series` and its kin — is not a tag.
+Why: cross-type discovery is the point of a single-author site; one term spanning a comic, a poem and a
+photo essay is the feature, not the noise. Per-section pools would fragment that to solve a readability
+problem the View solves by grouping. And a free-form cross-cutting tag behaves nothing like a fixed term
+set that drives engine behaviour, so conflating them makes both worse.
+Consequence: cheap — one Query with an optional section predicate serves both listings, and the second
+caller is what earned `Query.Tag` rather than a guess. Expensive — tag hygiene is the author's discipline
+since nothing scopes terms, so `check` owes a near-duplicate report; and `tags` is now reserved at the top
+level and inside every section.
+Revisit if: the pool becomes unusable in practice — and then the answer is curation, not namespacing.

docs/state.md

@@ -1,6 +1,6 @@
 # State
 
-**Verified against:** `449850c` on 2026-07-30 — update this line every change.
+**Verified against:** `fbf24f7` on 2026-07-30 — update this line every change.
 If this file disagrees with the code, the code is right and this file is a bug.
 
 ## Inventory

ideas/deferred-decisions.md

@@ -76,26 +76,13 @@ sets a policy once for everything beneath it. Expensive — resolution must be c
 runs per bundle, and the set of cascadable keys must stay declared or it becomes unbounded config.
 Revisit if: cascade resolution shows up in a render-path profile.
 
-## Taxonomies and feed shape
+## Feed shape
 
-Deferred because no tag pages and no feeds in the MVP.
+Deferred because no feeds exist yet. The tag half of this became ADR-0032 when tags were built.
 
-## Global flat tags, declared structural taxonomies
+Recorded direction: `/feed.xml` carries every type declared `primary`, `/{section}/feed.xml` carries a
-Date: 2026-07-28 · Status: accepted
+section, and `/tags/{term}/feed.xml` falls out of the same Query. Which types are `primary` is part of the
-Decision: `tags` is one global namespace across every type — `/tags/{tag}/` lists everything carrying it,
+type declaration, so this and declared types land together.
-`/{section}/tags/{tag}/` narrows to a section, and listing views group results by type. Structural
-metadata with known terms that drives behaviour — `series`, `medium`, `genre` — is a *declared* taxonomy
-on the type (ADR-0014) and never enters the tag pool. Feeds follow the same shape: `/feed.xml` carries
-every type declared `primary`, `/{section}/feed.xml` carries a section, `/tags/{tag}/feed.xml` falls out
-of the same Query.
-Why: cross-type discovery is the point of a single-author site — one tag spanning a comic, a poem and a
-photo essay is a feature. Per-section tag pools would fragment that for a readability problem better
-solved by grouping in the View. But a tag is free-form and cross-cutting, while a structural taxonomy has
-a fixed term set and changes what the engine does; conflating them makes both worse.
-Consequence: cheap — one Query with an optional section predicate serves tag pages, section tag pages and
-their feeds. Expensive — tag hygiene is now the author's discipline, since nothing scopes them; the
-content `check` command should report near-duplicate terms.
-Revisit if: the tag pool becomes unusable in practice — and then the answer is curation, not namespacing.
 
 ## Extras