Sync Astro types before the typecheck too

Second failure on the same step, same shape as the first: the typecheck
passed locally because .astro/types.d.ts was lying around from an
earlier build. CI runs the typecheck before the build, so `astro:content`
and `import.meta.env` had no declarations there.

`astro sync` writes that file without a full build, so it now runs first
in the typecheck chain.

Verified in a clean clone this time rather than in the working tree:
git clone to a temp dir, npm ci, npm run typecheck -- 0 errors -- and
npm run build -- 646 pages. Checking a generated-file problem from a
directory that already has the generated files is what produced both of
these failures.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

Author: sametbasbug

package.json

@@ -18,7 +18,7 @@
     "build": "astro build",
     "build:ssr": "astro build --config astro.config.ssr.mjs",
     "deploy": "wrangler deploy --config wrangler.ssr.jsonc",
-    "typecheck": "npm run types:gen && tsc --noEmit -p tsconfig.json",
+    "typecheck": "astro sync && npm run types:gen && tsc --noEmit -p tsconfig.json",
     "types:gen": "wrangler types --config wrangler.ssr.jsonc",
     "preview": "astro preview",
     "astro": "astro",