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>

server.ts

@@ -0,0 +1,82 @@
+import "./src/bootstrap/async-local-storage-polyfill";
+import { createServer } from "node:http";
+import path from "node:path";
+import { fileURLToPath } from "node:url";
+import next from "next";
+import { WebSocketServer } from "ws";
+import { getConfig } from "./src/lib/config/load";
+import { migrateOnBoot } from "./src/lib/db/client";
+import { syncAuthFromConfig } from "./src/lib/auth/sync";
+import { reconcileOrphanedRuns } from "./src/lib/runner/engine";
+import { killAllRuns } from "./src/lib/runner/registry";
+import { attachWsServer, authenticateUpgrade } from "./src/lib/ws/server";
+
+const dev = process.env.NODE_ENV !== "production";
+const { config } = getConfig();
+
+const port = Number(process.env.PORT ?? config.server.port);
+const hostname = process.env.HOST ?? config.server.host;
+
+migrateOnBoot();
+syncAuthFromConfig();
+reconcileOrphanedRuns();
+
+// `dir` must be this file's own directory, not `process.cwd()` - when launched by the installed
+// `triggershell` CLI, the working directory is wherever the user's config lives, not the package.
+const dir = path.dirname(fileURLToPath(import.meta.url));
+// Exposed via `process.env` (not just the local `dir` const) so Route Handlers/Server Components -
+// compiled through Next's own module graph, separate from this file's - can find it too. See
+// `docs.ts`'s use of this and the `globalThis` comment in `runner/events.ts` for the same reasoning.
+process.env.TRIGGERSHELL_APP_ROOT = dir;
+const app = next({ dev, dir, hostname, port });
+const handle = app.getRequestHandler();
+
+app.prepare().then(() => {
+  const nextUpgradeHandler = app.getUpgradeHandler();
+
+  const httpServer = createServer((req, res) => {
+    handle(req, res);
+  });
+
+  const wss = new WebSocketServer({ noServer: true });
+  attachWsServer(wss);
+
+  httpServer.on("upgrade", (req, socket, head) => {
+    const { pathname } = new URL(req.url ?? "/", "http://internal");
+    if (pathname !== "/ws/runs") {
+      // Anything else (e.g. Next's own dev-mode HMR websocket at /_next/hmr) is Next's to handle.
+      nextUpgradeHandler(req, socket, head).catch(() => socket.destroy());
+      return;
+    }
+
+    authenticateUpgrade(req)
+      .then((ok) => {
+        if (!ok) {
+          socket.write("HTTP/1.1 401 Unauthorized\r\n\r\n");
+          socket.destroy();
+          return;
+        }
+        wss.handleUpgrade(req, socket, head, (ws) => {
+          wss.emit("connection", ws, req);
+        });
+      })
+      .catch(() => socket.destroy());
+  });
+
+  httpServer.listen(port, hostname, () => {
+    console.log(
+      `> triggershell ready on http://${hostname}:${port} (${dev ? "development" : "production"})`,
+    );
+  });
+
+  const shutdown = (signal: string) => {
+    console.log(`> received ${signal}, shutting down...`);
+    killAllRuns();
+    httpServer.close(() => process.exit(0));
+    // Force-exit if graceful shutdown hangs (e.g. a stuck WS connection).
+    setTimeout(() => process.exit(1), 5000).unref();
+  };
+
+  process.on("SIGTERM", () => shutdown("SIGTERM"));
+  process.on("SIGINT", () => shutdown("SIGINT"));
+});