chs: re-add drifted files

dot_agents/skills/blume-migrate/SKILL.md

@@ -70,7 +70,7 @@ The single biggest shift for most sources — especially Mintlify — is that **
 - **`navigation`:** `tabs`, `selectors`, `featured` (links pinned above the sidebar on every route), `sidebar` (`{ display, items }` — `display` is the global render mode above; `items` is an explicit tree), `repo`. **Avoid an explicit `navigation.sidebar` unless you have to** — lean on the filesystem-derived sidebar. It only works when the file tree roughly matches the intended sidebar layout, so reshape folders to match first; reach for `sidebar.items` only for a shape files genuinely can't express (see "Config-declared nesting" above).
 - **`search`** (Orama default, Pagefind opt-in), **`ai`** (llms.txt, Ask AI, the MCP server), **`openapi`**, **`redirects`**, **`seo`**, **`markdown`**, **`analytics`**, **`deployment`**, **`i18n`**, **`toc`**, **`lastModified`**, **`github`**.
 - **Don't set `deployment.site`.** Blume auto-fills it: the dev server's `localhost` URL in dev, and the deployment URL (`VERCEL_PROJECT_PRODUCTION_URL`/`VERCEL_URL`) on Vercel. Hardcoding it in `blume.config.ts` overrides that auto-detection and pins the wrong absolute URL (canonical links, sitemap, OG, llms.txt) everywhere but the one host you typed — so leave it unset even when a source config had a `url`/`site` field. (Sitemap still generates in production because the deploy URL is present there.)
-- **Favicon is a filename convention, not config.** Drop `icon`/`favicon.{svg,png,ico}` (and `apple-icon.png`) in the project root or `public/` — Blume auto-detects it. There is **no** `favicon` config field. A source favicon given as `{ light, dark }` **collapses to one** — pick a single file and report the loss.
+- **Favicon is a filename convention, not config.** Drop `icon`/`favicon.{svg,png,ico}` (and `apple-icon.png`) in the project root or `public/` — Blume auto-detects it. There is **no** `favicon` config field. A source favicon given as `{ light, dark }` maps to a filename pair: copy the light file to a conventional name (e.g. `public/icon.png`) and the dark file to its `-dark` sibling — same directory and extension, `-dark` before the extension (`public/icon-dark.png`). If the two files have different formats, convert one so the extensions match; only an exact sibling of the resolved icon is picked up.
 
 The schema is exported from `blume/schema`; the full field reference is in the `docs/configuration/` directory of the installed `blume` package (see "Full documentation" below for how to locate it).