[meaningfool]

Since meaningfool/meaningfool-writing#6, every article has a topics frontmatter field. That leaves the hard-coded topics in src/data/topics.ts as dead code that could drift from the frontmatter. This PR removes them. It's a technical change: the rendered site doesn't change.

Changes

• src/data/topics.ts: removes the fromPrototype list, unknownTopicIds, topicsOf and the CollectionEntry import that only topicsOf used. Without the fallback, topicsOf only returned article.data.topics, so it is inlined. Kept: TOPICS (the topics schema in src/content.config.ts uses it), Topic, TOPIC_NAMES and the check that topic-map.json's topics match TOPICS. The header comment is rewritten.
• src/pages/index.astro: reads article.data.topics. Removes the unknownTopicIds import and its warning loop, and the header comment now points at the frontmatter field instead of src/data/topics.ts. The warning for an article with no topics stays.
• src/content.config.ts: the comment no longer says articles without the field take their topics from src/data/topics.ts. It says activity logs don't need the field and that the home warns about an article without it.
• AGENTS.md: drops ", or else its entry in src/data/topics.ts".

I searched the repository for fromPrototype, unknownTopicIds, topicsOf and data/topics. Outside docs/redesign/prototype/, which this PR leaves alone, the only matches left are the imports of TOPICS and TOPIC_NAMES, and the error message of the kept topic-map.json check.

Validation

Head commit: 815a56941bed7ccd0d1f92498340becc59481b85. Base: main at e8c17cc. Node 24.22.1, Bun 1.4.4. Content: the submodule at meaningfool-writing main, c6ed223 ("Merge pull request #6: Give each article its topics in the frontmatter"), fetched with git submodule update --init --remote. All 18 articles have topics. The submodule pointer is not part of this PR, and nothing was committed in the submodule.

Check	Command	Result
Build before (main)	bun run build	Passes: 62 pages, no warnings
Build after (this branch)	bun run build	Passes: 62 pages, no warnings (the build logs differ only in timings, the image cache and Astro's "Content config changed" note)
Compare dist/	diff -rq, and sha256sum of every file	157 files on each side. 155 are byte-identical. llms.txt and llms-full.txt differ only in their Generated: timestamps. The home's data-topics are unchanged: 8 ai-agents, 5 product, 3 product ai-agents, 1 customer-success product, 1 customer-success product ai-agents
Document tests	bun run test:documents	10 pass, 0 fail
Article without topics (uncommitted submodule edit, reverted)	Deleted the topics: line of the-slicing-fallacy, then bun run build	Passes and prints "the-slicing-fallacy" has no topics, so picking a topic on the home's map hides it: give it a topics field.
Value outside the three ids (uncommitted submodule edit, reverted)	Set topics: ["product", "design"] on the-slicing-fallacy, then bun run build	Fails: InvalidContentEntryDataError … topics.1: Invalid option: expected one of "customer-success"|"product"|"ai-agents"
Clean rebuild after reverting both edits	bun run build	Passes. dist/ matches the "before" checksums again, apart from the two llms timestamps

Please don't merge without the owner's go-ahead.

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