chore(llm): relocate skills to assets

CLAUDE.md

@@ -153,6 +153,12 @@ Trilium provides powerful user scripting capabilities:
 - Add migration scripts in `apps/server/src/migrations/`
 - Update schema in `apps/server/src/assets/db/schema.sql`
 
+### Server-Side Static Assets
+- Static assets (templates, SQL, translations, etc.) go in `apps/server/src/assets/`
+- Access them at runtime via `RESOURCE_DIR` from `apps/server/src/services/resource_dir.ts` (e.g. `path.join(RESOURCE_DIR, "llm", "skills", "file.md")`)
+- **Do not use `import.meta.url`/`fileURLToPath`** to resolve file paths — the server is bundled into CJS for production, so `import.meta.url` will not point to the source directory
+- **Do not use `__dirname` with relative paths** from source files — after bundling, `__dirname` points to the bundle output, not the original source tree
+
 ## Build System Notes
 - Uses pnpm for monorepo management
 - Vite for fast development builds

apps/server/src/services/llm/skills/index.ts

@@ -4,13 +4,15 @@
  * included in the system prompt; full content is fetched via the load_skill tool.
  */
 
-import { tool } from "ai";
 import { readFile } from "fs/promises";
-import { dirname, join } from "path";
-import { fileURLToPath } from "url";
+import { join } from "path";
+
+import { tool } from "ai";
 import { z } from "zod";
 
-const __dirname = dirname(fileURLToPath(import.meta.url));
+import resourceDir from "../../resource_dir.js";
+
+const SKILLS_DIR = join(resourceDir.RESOURCE_DIR, "llm", "skills");
 
 interface SkillDefinition {
     name: string;
@@ -41,7 +43,7 @@ async function loadSkillContent(name: string): Promise<string | null> {
     if (!skill) {
         return null;
     }
-    return readFile(join(__dirname, skill.file), "utf-8");
+    return readFile(join(SKILLS_DIR, skill.file), "utf-8");
 }
 
 /**