fix: process embeddings sequentially, shorten prompts, fix tests

- main.ts: process files sequentially (not Promise.all) to avoid concurrent
  embedding requests hammering Ollama; batch size reduced to 1
- vectorization.ts: shorten embedding prompts from 1000 to 500 chars,
  limit headings to 5, remove frontmatter from prompt to stay well within
  embedding model context window
- Update vectorization and indexing-pipeline tests for new prompt format

main.js

@@ -9507,10 +9507,10 @@ var ContentVectorizer = class {
     const parts = [
       chunk.title,
       chunk.firstParagraph,
-      chunk.content.substring(0, 1e3),
+      chunk.content.substring(0, 500),
       // Limit content to avoid long prompts
-      chunk.headings.join(" "),
-      JSON.stringify(chunk.frontmatter)
+      chunk.headings.slice(0, 5).join(" ")
+      // Limit headings
     ].filter(Boolean);
     return parts.join("\n\n");
   }
@@ -10033,7 +10033,7 @@ var OllamaPlugin = class extends import_obsidian4.Plugin {
     const files = this.app.vault.getMarkdownFiles();
     Logger.info(`Starting background vault indexing for ${files.length} files...`, "main");
     let indexed = 0;
-    const BATCH_SIZE = 2;
+    const BATCH_SIZE = 1;
     const DELAY_MS = 500;
     for (let i = 0; i < files.length; i += BATCH_SIZE) {
       if (signal.aborted) {
@@ -10041,20 +10041,18 @@ var OllamaPlugin = class extends import_obsidian4.Plugin {
         return;
       }
       const batch = files.slice(i, i + BATCH_SIZE);
-      await Promise.all(
-        batch.map(async (file) => {
-          if (signal.aborted) return;
-          try {
-            const content = await this.app.vault.read(file);
-            if (signal.aborted) return;
-            await this.vaultVectorStore.indexFile(file, content);
-            indexed++;
-          } catch (error) {
-            const errorMessage = error instanceof Error ? error.message : String(error);
-            Logger.warn(`Failed to index ${file.path}: ${errorMessage}`, "main");
-          }
-        })
-      );
+      for (const file of batch) {
+        if (signal.aborted) break;
+        try {
+          const content = await this.app.vault.read(file);
+          if (signal.aborted) break;
+          await this.vaultVectorStore.indexFile(file, content);
+          indexed++;
+        } catch (error) {
+          const errorMessage = error instanceof Error ? error.message : String(error);
+          Logger.warn(`Failed to index ${file.path}: ${errorMessage}`, "main");
+        }
+      }
       if (i + BATCH_SIZE < files.length) {
         await new Promise((resolve) => setTimeout(resolve, DELAY_MS));
       }