Flatten the repo: move everything out of app/ to the root

Now that the CLI and the Next.js app are one package, nesting it inside
app/ served no purpose - the repo root itself becomes the published
npm package. Merges app/.gitignore and app/README.md into the root
versions, drops the now-duplicate app/LICENSE, and updates path
references (README, docs/ARCHITECTURE.md, docs/CONFIG_REFERENCE.md,
package.json's repository.directory) that assumed the app/ nesting.

Also fixes a real bug this surfaced: the in-app docs viewer resolved
docs/ relative to process.cwd(), which only worked by accident when the
CLI happened to be invoked from app/'s parent directory. A first attempt
at fixing it with import.meta.dirname broke instead, for the same
cross-module-graph reason config-path resolution already documented -
Next compiles Route Handlers through a separate module graph that
doesn't preserve source-relative import.meta paths. Fixed by exposing
the app root via TRIGGERSHELL_APP_ROOT (set once in server.ts, where
import.meta *does* resolve correctly), the same pattern already used
for TRIGGERSHELL_CONFIG_PATH.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

src/lib/docs.ts

@@ -0,0 +1,45 @@
+import fs from "node:fs";
+import path from "node:path";
+
+export interface DocMeta {
+  slug: string;
+  title: string;
+  description: string;
+  file: string;
+}
+
+export const DOCS: DocMeta[] = [
+  {
+    slug: "api",
+    title: "API Reference",
+    description: "REST and WebSocket endpoints, auth, and request/response shapes.",
+    file: "API.md",
+  },
+  {
+    slug: "config",
+    title: "Config Reference",
+    description: "Every field in triggershell.yml: server, auth, scripts, and variables.",
+    file: "CONFIG_REFERENCE.md",
+  },
+];
+
+export function getDocMeta(slug: string): DocMeta | undefined {
+  return DOCS.find((doc) => doc.slug === slug);
+}
+
+// Resolved from TRIGGERSHELL_APP_ROOT (set once in server.ts), not `process.cwd()` or
+// `import.meta.dirname` - this file is read from a Route Handler compiled through Next's own
+// module graph, which is a separate module instantiation from server.ts and doesn't preserve
+// source-relative `import.meta` paths (see the `globalThis` comment in `runner/events.ts`).
+// Falls back to a source-relative resolution for contexts where server.ts never ran (e.g. tests).
+function docsDir(): string {
+  const appRoot =
+    process.env.TRIGGERSHELL_APP_ROOT ?? path.resolve(import.meta.dirname, "..", "..");
+  return path.resolve(appRoot, "docs");
+}
+
+export function readDocContent(doc: DocMeta): string | null {
+  const filePath = path.join(docsDir(), doc.file);
+  if (!fs.existsSync(/*turbopackIgnore: true*/ filePath)) return null;
+  return fs.readFileSync(/*turbopackIgnore: true*/ filePath, "utf-8");
+}