perf(blog): comprehensive performance optimization

- Remove KaTeX (unused math rendering) - saves ~23KB CSS
- Remove Giscus comments system
- Convert favicon.png to SVG - saves 928KB
- Remove unused Atkinson fonts - saves 45KB
- Optimize Pretendard font loading (non-blocking)
- Resize large WebP images (oop, main, nlp) - saves 9.3MB
- Convert 78 PNG files to WebP - saves 3.7MB
- Add scroll event throttling with requestAnimationFrame
- Add native image lazy loading
- Add HTTP caching headers (_headers)
- Enable Astro prefetch for faster navigation
- Update translate workflow trigger to main push

Total savings: ~14MB+

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: ppippi-dev

.github/workflows/translate-to-english.yml

@@ -1,8 +1,11 @@
 name: Translate new posts to English
 
 on:
-  pull_request:
-    types: [opened, synchronize, reopened]
+  push:
+    branches:
+      - main
+    paths:
+      - 'src/content/blog/**/*.md'
 
 permissions:
   contents: write
@@ -11,31 +14,17 @@ jobs:
   translate:
     runs-on: ubuntu-latest
     steps:
-      - name: Checkout PR branch
+      - name: Checkout main branch
         uses: actions/checkout@v4
         with:
-          ref: ${{ github.head_ref }}
+          fetch-depth: 2
 
-      - name: Get changed files from PR
+      - name: Get changed blog posts
         id: changes
-        uses: actions/github-script@v7
-        with:
-          script: |
-            const pr = context.payload.pull_request;
-            const { owner, repo } = context.repo;
-            const pull_number = pr.number;
-            const per_page = 100;
-            let page = 1;
-            const files = [];
-            while (true) {
-              const res = await github.rest.pulls.listFiles({ owner, repo, pull_number, per_page, page });
-              if (res.data.length === 0) break;
-              for (const f of res.data) files.push(f.filename);
-              if (res.data.length < per_page) break;
-              page += 1;
-            }
-            const posts = files.filter(f => f.startsWith('src/content/blog/') && f.endsWith('.md'));
-            core.setOutput('posts', posts.join('\n'));
+        run: |
+          POSTS=$(git diff --name-only HEAD~1 HEAD -- 'src/content/blog/*.md' | tr '\n' ' ')
+          echo "posts=$POSTS" >> $GITHUB_OUTPUT
+          echo "Changed posts: $POSTS"
 
       - name: Set ONLY_FILES env
         if: steps.changes.outputs.posts != ''
@@ -68,6 +57,6 @@ jobs:
         if: steps.changes.outputs.posts != ''
         uses: stefanzweifel/git-auto-commit-action@v5
         with:
-          commit_message: "chore: add English translations for PR #${{ github.event.pull_request.number }}"
+          commit_message: "chore: add English translations"
           file_pattern: 'src/content/blog-en/*.md'
           add_options: '-A'

astro.config.mjs

@@ -3,8 +3,6 @@
 import mdx from '@astrojs/mdx';
 import sitemap from '@astrojs/sitemap';
 import { defineConfig } from 'astro/config';
-import remarkMath from 'remark-math';
-import rehypeKatex from 'rehype-katex';
 import { redirects } from './src/redirects';
 
 // https://astro.build/config
@@ -18,9 +16,9 @@ export default defineConfig({
 				!Object.keys(redirects).some((oldPath) => page.endsWith(oldPath)),
 		}),
 	],
-	markdown: {
-		remarkPlugins: [remarkMath],
-		rehypePlugins: [rehypeKatex],
-	},
 	redirects,
+	prefetch: {
+		prefetchAll: true,
+		defaultStrategy: 'viewport',
+	},
 });

package-lock.json

@@ -15,8 +15,6 @@
     "@astrojs/sitemap": "^3.6.0",
     "@pagefind/default-ui": "^1.4.0",
     "astro": "^5.16.5",
-    "rehype-katex": "^7.0.1",
-    "remark-math": "^6.0.0",
     "sharp": "^0.34.3"
   }
 }

package.json

@@ -0,0 +1,21 @@
+# Static assets - long cache (1 year)
+/_astro/*
+  Cache-Control: public, max-age=31536000, immutable
+
+/fonts/*
+  Cache-Control: public, max-age=31536000, immutable
+
+# Images - medium cache (30 days)
+/img/*
+  Cache-Control: public, max-age=2592000
+
+/favicon*
+  Cache-Control: public, max-age=2592000
+
+# Pagefind search index
+/pagefind/*
+  Cache-Control: public, max-age=86400
+
+# HTML pages - no cache (always fresh)
+/*
+  Cache-Control: public, max-age=0, must-revalidate