v3: comments say what the code can't — the documentation pass wanted JSDoc on every export and every field of an exported interface, which filled the code with restatements ("The dump.", "Whether it is loading.", "The props of X.", "Renders the X.") and module docs that told a reader nothing ("The hot and new feeds, and the props every main feed of the index takes."); some were wrong as well as vague. Every comment in api/, shared/ and src/ is rewritten under one rule, now stated in the README's "Comments" section: every module and export still has a JSDoc, and it gives context (who uses it and where), usage (what a caller must know: a precondition, what it leaves to the caller, a side effect) or its place in the chain (where its input comes from, where its output goes); a field, parameter, private function or local gets one only when it adds to its parent's, and context about a whole type goes on the type; a type's doc is phrased from the value's side ("Returned to Y by X when Z", "Passed to Y by X"); full sentences, as short as they can be, no label-colon-list; // goes wherever the code isn't obvious and says why, and the section banners and narration go. Every claim was checked against the code, which turned up some forty comments that were wrong: DumpCard's claimed it was only used by the hot and new feeds, the WebSocket welcome claimed to be a socket's first message (presence comes first), UpdateUserRequest said null removes a description (it keeps it), deletedDumpIds leaves out that it also holds dumps made private, THEME_COLOR claimed to mirror index.html's, and the like. The routers' JSDoc now says where they are mounted and what becomes of a thrown APIException. doc-lint.ts lets a field without a doc through; a module or export without one still fails. No code changes; 204 backend and 628 frontend tests pass, and doc:lint, deno check, deno lint and tsc are clean.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

api/db/migrate.ts

@@ -1,6 +1,7 @@
 /**
- * Brings an existing database up to date with the migrations under
- * migrations/, recording each applied one in `schema_migrations`.
+ * Brings the database up to date with the migrations under migrations/, and
+ * records each one it applies in `schema_migrations`. connection.ts runs it
+ * each time the server opens the database.
  *
  * @module
  */
@@ -29,10 +30,10 @@ interface Migration {
 }
 
 /**
- * Every migration, in order. Append-only — never edit or reorder a migration
- * once it has shipped. Each `up` must be idempotent: it also runs against
- * fresh databases created straight from schema.sql, where the change it makes
- * already exists.
+ * Every migration, in the order they run. A new one goes at the end, along
+ * with the same change to schema.sql, and a shipped one is never edited or
+ * moved. A database made by init.ts records none of them, so each `up` must
+ * find its change already made and leave it be.
  */
 const MIGRATIONS: Migration[] = [
   { name: "0001_comment_likes", up: up0001CommentLikes },
@@ -57,11 +58,11 @@ const MIGRATIONS: Migration[] = [
 ];
 
 /**
- * Applies each migration `db` hasn't recorded yet, each in its own
+ * Applies each migration `db` hasn't recorded yet, in order, each in its own
  * transaction.
  *
- * @throws {Error} When a migration fails; that migration is rolled back and
- * the later ones aren't run.
+ * @throws {Error} When a migration fails. That one is rolled back, the later
+ * ones don't run, and the server doesn't start.
  */
 export function runMigrations(db: DatabaseSync): void {
   db.exec(`CREATE TABLE IF NOT EXISTS schema_migrations (