feat(admin): add ephemeral staging DB, read-only posts overview, and dynamic search

- Implement ephemeral staging mode (APP_ENV=staging) to isolate test/dev DB writes in /tmp
- Add read-only posts management dashboard under /guanli/posts with live links and comment counters
- Add hot re-indexing endpoint (/guanli/reindex) to refresh Markdown without restarting server
- Replace static recommended search config with dynamic frequency-based trending searches
- Remove early scaffold mockup file (dropbox/zh.md) and clean legacy mock test queries
- Add native Makefile with dev, dev-persistent, test, lint, and docker targets
- Update test suite and documentation for development workflows

server/routes/search.js

@@ -5,7 +5,6 @@ const contentService = require('../services/content');
 const { loadSiteConfig } = require('../config');
 
 function getRecommendedSearches() {
-  const config = loadSiteConfig();
   const taxonomy = contentService.getTaxonomy();
   const dbService = require('../services/db');
 
@@ -29,26 +28,19 @@ function getRecommendedSearches() {
     });
   }
 
-  // 3. Add top trending searches from SQLite database
-  const trendingDb = dbService.getTopSearchRecommendations(4);
+  // 3. Add genuine trending searches by frequency from search_logs (result_count > 0)
+  const trendingDb = dbService.getTopSearchQueries(6);
   const customPills = [];
   for (const item of trendingDb) {
-    if (!dynamicPills.some(p => p.query === item.query)) {
+    if (!dynamicPills.some(p => p.query.toLowerCase() === item.query.toLowerCase())) {
       customPills.push({
         label: item.label,
-        query: item.query
+        query: item.query,
+        frequency: item.frequency
       });
     }
   }
 
-  // 4. Add any static curated pills from config
-  const staticConfig = (config.search && config.search.recommended) || [];
-  for (const item of staticConfig) {
-    if (!dynamicPills.some(p => p.query === item.query) && !customPills.some(p => p.query === item.query)) {
-      customPills.push(item);
-    }
-  }
-
   return {
     dynamicPills,
     customPills