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/daily-finds/SKILL.md

@@ -57,7 +57,7 @@ For each extracted item, drop:
 For every survivor, write one file at `src/content/find/<year>/<month>/<slug>/index.mdx` where `<year>` and `<month>` come from today's date. Hero image (when present) sits next to it as `src/content/find/<year>/<month>/<slug>/hero.<ext>`. The leaf folder name is the slug; URLs stay flat at `/find/<slug>/` because the content-collection loader uses a `leafSlug` id derivation.
 
 - Slug: kebab-case form of the name (lowercase, ASCII, no leading numbers).
-- Frontmatter: `name`, `subtitle` (optional, one-liner), `date` (today), `link` (external URL — required), `linkText` (optional), `source` (the source name from sources.json — required, exact match), `topics` (copied from the source's `topics`), `tags` (free editorial tags inferred from the item — keep to 2-4), `description` (optional meta override).
+- Frontmatter: `name`, `subtitle` (optional, one-liner), `date` (today), `link` (external URL — required), `linkText` (optional), `source` (the source name from sources.json — required, exact match), `topics` (1-3 values chosen from the controlled vocabulary in `src/lib/topics.ts` — the `TOPIC_META` keys; judge from the item itself, the source's `topics` in sources.json are hints only and may contain retired values; the build fails on anything outside the vocabulary; `[]` if nothing genuinely fits), `tags` (free editorial tags inferred from the item — keep to 2-4; add `giftable` when the item would make a genuinely good gift), `description` (optional meta override).
 - Body: 2-3 sentence note. Concrete, name a *specific* virtue. Bad: "great design". Good: "the silicone bumper means it survives drops onto concrete; the lanyard hole is positioned where your thumb naturally rests".
 - No daily cap — write every survivor.