site: topics axis + per-source indexes

Topics — the curated subscription layer: 18-value controlled vocabulary
in src/lib/topics.ts, enum-enforced by the content schema on finds and
reviews so unattended runs can't drift it. /topics/ index +
/topics/<t>/ pages with finds first-class alongside reviews, per-topic
RSS feeds that include finds (unlike category/tag feeds), "By topic"
section on /feeds/, Topics footer link and llms.txt section, dev-shim
coverage for the new feed URLs. daily-finds and build-review skills now
classify at capture/graduation time; "giftable" is a tag, never a
topic.

Per-source indexes: /sources/<slug>/ lists every review and find from a
source (catalog ∪ names in content, so retired sources resolve);
find/review colophons link "(more from this source)"; /sources/ cards
link "everything from this source →"; sub-3-item pages noindexed.

Claude-Session: https://claude.ai/code/session_01WZaczDJjL3xZ3u5spsN5AL

.claude/skills/build-review/SKILL.md

@@ -77,6 +77,7 @@ name: "<from the find>"
 subtitle: "<from the find — required for reviews>"
 date: YYYY-MM-DD             # today (the review date), not the find's date
 category: <pick from existing categories or propose a new one>
+topics: <1-3 from the controlled vocabulary in src/lib/topics.ts (TOPIC_META keys) — usually the find's topics, adjusted if the review's angle differs; build fails on values outside the vocabulary>
 tags: <merge the find's tags with any review-specific additions>
 link: "<from the find — or a better canonical URL surfaced by step 3>"
 linkText: "<from the find, if set>"