feat: upgrade to Astro 7

AGENTS.md

@@ -5,7 +5,7 @@ blog. This file is the source of truth for conventions; read it before making ch
 
 ## What this is
 
-- **Astro 6**, `output: "static"` — prerendered HTML. Deployed to **Cloudflare Workers
+- **Astro 7**, `output: "static"` — prerendered HTML. Deployed to **Cloudflare Workers
   Static Assets** (`./dist`). A thin Worker (`worker/index.ts`) sits in front purely for
   `Accept: text/markdown` content negotiation; everything else is static. Fingerprinted
   assets are still served directly (see `run_worker_first` in `wrangler.jsonc`).
@@ -230,6 +230,22 @@ visual changes, check at both mobile and desktop widths.
 
 CI does **not** deploy; Cloudflare's Git integration deploys on push to `main`.
 
+## Commits & PRs
+
+- **Conventional Commits.** Every commit message follows the
+  [Conventional Commits](https://www.conventionalcommits.org/) spec:
+  `type(scope): summary` (e.g. `feat(feed): …`, `fix(og): …`,
+  `build(deps): …`, `docs: …`, `chore(config): …`). Use the same convention
+  for branch names.
+- **Small, meaningful commits.** Split a change into focused commits that each
+  do one coherent thing (e.g. dependency bumps, config change, and docs as
+  separate commits) rather than one large catch-all. Each commit should build
+  and make sense on its own.
+- **Verify before committing.** Run the [Build & verify](#build--verify) steps;
+  don't commit work that fails `check` or `build`.
+- **Branch off `main`** for new work, open a PR, and let CI run. Cloudflare
+  deploys from `main` on merge — don't push directly to `main`.
+
 ## Do NOT touch (unless that's explicitly the task)
 
 - `astro.config.mjs`, `tsconfig.json`, `wrangler.jsonc` — infra; change deliberately.
@@ -254,6 +270,10 @@ CI does **not** deploy; Cloudflare's Git integration deploys on push to `main`.
   island (`client:visible`), which is handed the whole feed and reveals more posts in
   place. "Load more" is a real link to `/…/page/N/`, so without JS it just navigates
   there — those static `/page/N/` routes are the no-JS / crawler fallback, so keep them.
-- Remark plugins are registered in `astro.config.mjs` via
-  `markdown.processor: unified({ remarkPlugins: [...] })` (NOT the deprecated
-  `markdown.remarkPlugins`); `shikiConfig` stays at the top-level `markdown` key.
+- Astro 7's default Markdown processor is **Sätteri** (Rust). This blog opts back
+  into the **unified (remark/rehype)** pipeline because its remark plugins are
+  unified plugins: `markdown.processor: unified({ remarkPlugins: [...] })` in
+  `astro.config.mjs`, with `unified` imported from the explicitly-installed
+  **`@astrojs/markdown-remark`** dependency (Astro 7 no longer bundles it).
+  `shikiConfig` stays at the top-level `markdown` key. `compressHTML: true` is
+  pinned to keep v6 whitespace behavior (Astro 7's default is `'jsx'`).

astro.config.mjs

@@ -15,6 +15,10 @@ export default defineConfig({
   output: 'static',
   // Trailing slashes on every URL (enforced globally).
   trailingSlash: 'always',
+  // Astro 7 changed the default from `true` to `'jsx'` (collapses whitespace
+  // between inline elements using JSX rules). Pin to `true` to keep the exact
+  // v6 HTML/whitespace behavior — this blog preserves its established look.
+  compressHTML: true,
   build: {
     // Emit /slug/index.html so URLs are /slug/.
     format: 'directory',
@@ -46,7 +50,10 @@ export default defineConfig({
     stripImageMetadata(),
   ],
   // Code blocks highlighted by Shiki with the Nord theme.
-  // remark plugins via processor API (markdown.remarkPlugins is deprecated in Astro 6.4+).
+  // Astro 7's default Markdown processor is Sätteri (Rust); we opt back into the
+  // unified (remark/rehype) pipeline via `processor: unified()` from the
+  // explicitly-installed @astrojs/markdown-remark, since our remark plugins
+  // (video embeds, image captions) are unified plugins.
   // shikiConfig stays at top-level markdown (unified() does not forward it to Shiki).
   markdown: {
     processor: unified({