feat: centralize native dep installation across plugins

Replace per-plugin npm install with a single aggregated npm install
in the quartz root. Plugins declaring requiresInstall in their quartz
manifest now have their peerDependencies collected and installed
together, letting npm resolve compatible versions across plugins.

quartz/plugins/loader/config-loader.ts

@@ -16,6 +16,7 @@ import {
 import {
   parsePluginSource,
   installPlugin,
+  installNativeDeps,
   getPluginEntryPoint,
   toFileUrl,
   isLocalSource,
@@ -236,12 +237,31 @@ export async function loadQuartzConfig(
   const enabledEntries = json.plugins.filter((e) => e.enabled)
   const manifests = new Map<string, PluginManifest>()
 
-  // Ensure all plugins are installed and collect manifests
+  // Ensure all plugins are installed and collect native deps
+  const allNativeDeps = new Map<string, Map<string, string>>()
   for (const entry of enabledEntries) {
     try {
       const gitSpec = parsePluginSource(entry.source)
-      await installPlugin(gitSpec, { verbose: false })
+      const result = await installPlugin(gitSpec, { verbose: false })
+      if (result.nativeDeps.size > 0) {
+        allNativeDeps.set(gitSpec.name, result.nativeDeps)
+      }
+    } catch (err) {
+      console.error(
+        styleText("red", `✗`) +
+          ` Failed to install plugin: ${styleText("yellow", entry.source)}\n` +
+          `  ${err instanceof Error ? err.message : String(err)}`,
+      )
+    }
+  }
 
+  if (allNativeDeps.size > 0) {
+    installNativeDeps(allNativeDeps, { verbose: false })
+  }
+
+  // Collect manifests (requires native deps to be installed first)
+  for (const entry of enabledEntries) {
+    try {
       const manifest = await getManifest(entry.source)
       if (manifest) {
         manifests.set(entry.source, manifest)
@@ -249,7 +269,7 @@ export async function loadQuartzConfig(
     } catch (err) {
       console.error(
         styleText("red", `✗`) +
-          ` Failed to install plugin: ${styleText("yellow", entry.source)}\n` +
+          ` Failed to load manifest: ${styleText("yellow", entry.source)}\n` +
           `  ${err instanceof Error ? err.message : String(err)}`,
       )
     }