feat: add completions API and scanning logic

Implement a new completions system that scans markdown files for
dice notation and headings. The server now exposes a
`/__COMPLETIONS.json`
endpoint and automatically recomputes the completion index when
files are added, updated, or deleted.

src/cli/commands/serve.ts

@@ -6,6 +6,10 @@ import { join, resolve, extname, sep, relative, dirname } from "path";
 import { watch } from "chokidar";
 import { fileURLToPath } from "url";
 import { createJournalServer } from "../journal.js";
+import {
+  scanCompletions,
+  type CompletionsPayload,
+} from "../completions/index.js";
 
 interface ContentIndex {
   [path: string]: string;
@@ -144,6 +148,7 @@ function createRequestHandler(
   contentDir: string,
   distDir: string,
   getIndex: () => ContentIndex,
+  getCompletions: () => CompletionsPayload,
 ) {
   return (req: IncomingMessage, res: ServerResponse) => {
     const url = req.url || "/";
@@ -155,6 +160,12 @@ function createRequestHandler(
       return;
     }
 
+    // 1b. 处理 /__COMPLETIONS.json
+    if (filePath === "/__COMPLETIONS.json") {
+      sendJson(res, getCompletions());
+      return;
+    }
+
     // 2. 处理 /static/ 目录（从 dist/web）
     if (filePath.startsWith("/static/")) {
       if (tryServeStatic(res, filePath, distDir)) {
@@ -196,6 +207,10 @@ export interface ContentServer {
    * 内容索引
    */
   index: ContentIndex;
+  /**
+   * 补全数据
+   */
+  completions: CompletionsPayload;
   /**
    * 关闭服务器
    */
@@ -212,11 +227,21 @@ export function createContentServer(
   host: string = "0.0.0.0",
 ): ContentServer {
   let contentIndex: ContentIndex = {};
+  let completionsIndex: CompletionsPayload = { dice: [], links: [] };
+
+  /** Re-scan completions from current content index (cached) */
+  function recomputeCompletions(): void {
+    completionsIndex = scanCompletions(contentIndex);
+    console.log(
+      `[completions] dice=${completionsIndex.dice.length} links=${completionsIndex.links.length}`,
+    );
+  }
 
   // 扫描内容目录生成索引
   console.log("扫描内容目录...");
   contentIndex = scanDirectory(contentDir);
   console.log(`已索引 ${Object.keys(contentIndex).length} 个文件`);
+  recomputeCompletions();
 
   // 监听文件变化
   console.log("监听文件变化...");
@@ -238,6 +263,7 @@ export function createContentServer(
           const relPath = "/" + relative(contentDir, path).split(sep).join("/");
           contentIndex[relPath] = content;
           console.log(`[新增] ${relPath}`);
+          if (relPath.endsWith(".md")) recomputeCompletions();
         } catch (e) {
           console.error(`读取新增文件失败：${path}`, e);
         }
@@ -254,6 +280,7 @@ export function createContentServer(
           const relPath = "/" + relative(contentDir, path).split(sep).join("/");
           contentIndex[relPath] = content;
           console.log(`[更新] ${relPath}`);
+          if (relPath.endsWith(".md")) recomputeCompletions();
         } catch (e) {
           console.error(`读取更新文件失败：${path}`, e);
         }
@@ -268,6 +295,7 @@ export function createContentServer(
         const relPath = "/" + relative(contentDir, path).split(sep).join("/");
         delete contentIndex[relPath];
         console.log(`[删除] ${relPath}`);
+        if (relPath.endsWith(".md")) recomputeCompletions();
       }
     });
 
@@ -279,6 +307,7 @@ export function createContentServer(
     contentDir,
     distPath,
     () => contentIndex,
+    () => completionsIndex,
   );
   const server = createServer(handleRequest);
 
@@ -298,6 +327,7 @@ export function createContentServer(
     server,
     watcher,
     index: contentIndex,
+    completions: completionsIndex,
     close() {
       console.log("关闭内容服务器...");
       server.close();