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/migrations/0011_split_favicon_thumbnail.ts

@@ -1,21 +1,14 @@
 /**
- * Moves favicon-shaped values out of `rich_content.thumbnailUrl` into the new
- * `faviconUrl` field.
+ * Moves site icons out of `rich_content.thumbnailUrl` into the new
+ * `faviconUrl`. The metadata fetch used to fall back on the page's icon, and
+ * then on a guessed `/favicon.ico`, so most thumbnails were a 16×16 icon, or a
+ * 404, that the UI stretched over a 128×72 box. It now stops at real artwork,
+ * and a missing `thumbnailUrl` means none, which the frontend draws a
+ * placeholder for. This gives the older rows that meaning.
  *
- * The extraction cascade used to end at the page's icon and then at a guessed
- * `${origin}/favicon.ico`, so `thumbnailUrl` was almost never empty — it just
- * held a 16×16 icon (or a 404) that the UI then cover-cropped into a 128×72
- * box. The cascade now stops at real artwork, and an absent `thumbnailUrl`
- * means "no artwork", which is what lets the frontend draw a placeholder.
- * This migration gives rows written before that change the same meaning.
- *
- * Purely local — it classifies the already-stored URL and makes no network
- * calls, so `accentColor` is deliberately not backfilled: the frontend derives
- * a stable hue from the hostname whenever one is missing, and
- * `refreshDumpMetadata` fetches the real color on demand.
- *
- * Idempotent: rows that already carry a `faviconUrl` are skipped, so a fresh
- * database built from schema.sql is a no-op.
+ * It judges the stored URL alone and fetches nothing, so it doesn't fill
+ * `accentColor`. The frontend derives a hue from the hostname when it is
+ * missing, and refreshing a dump's metadata fetches the real one.
  *
  * @module
  */
@@ -23,12 +16,9 @@
 import type { DatabaseSync } from "node:sqlite";
 
 /**
- * Checks whether a stored thumbnail URL is really a site icon.
- *
- * Deliberately loose. A false positive (a genuine cover image living under
- * `/assets/icons/`) renders contained on a tinted field instead of
- * cover-cropped — mildly wrong, never broken — so chasing them isn't worth the
- * extra rules.
+ * Checks whether a stored thumbnail URL is a site icon. It is loose on
+ * purpose, since artwork taken for an icon still shows whole on a tinted field,
+ * only not cropped to fill the box. 0012 fixes the rows it got wrong.
  */
 function isIconUrl(raw: string): boolean {
   let pathname: string;
@@ -41,7 +31,11 @@ function isIconUrl(raw: string): boolean {
     /\.(ico|svg)$/i.test(pathname);
 }
 
-/** Applies this migration to `db`. */
+/**
+ * Run once by `runMigrations`. It leaves alone a row that already has a
+ * `faviconUrl`, and one whose `rich_content` doesn't parse. 0012 undoes its
+ * mistakes.
+ */
 export function up(db: DatabaseSync): void {
   const rows = db.prepare(
     `SELECT id, rich_content FROM dumps
@@ -58,7 +52,7 @@ export function up(db: DatabaseSync): void {
     try {
       rich = JSON.parse(row.rich_content);
     } catch {
-      continue; // malformed payload — leave it untouched
+      continue;
     }
     if (rich.faviconUrl || !rich.thumbnailUrl) continue;
     if (!isIconUrl(rich.thumbnailUrl)) continue;