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/cli/commands/doctor.ts

@@ -0,0 +1,42 @@
+import fs from "node:fs";
+import { ConfigError, loadConfig } from "../../lib/config/load";
+import { isPortFree } from "../lib/network";
+import { resolveConfigPath } from "../lib/paths";
+
+export interface DoctorOptions {
+  config?: string;
+}
+
+export async function doctorCommand(opts: DoctorOptions): Promise<void> {
+  const rows: [string, string][] = [];
+
+  rows.push(["Node.js", process.version]);
+
+  const configPath = resolveConfigPath(opts.config);
+  const exists = fs.existsSync(configPath);
+  rows.push(["Config path", `${configPath} ${exists ? "(exists)" : "(not found)"}`]);
+
+  if (exists) {
+    try {
+      const { config } = loadConfig(configPath);
+      const portFree = await isPortFree(config.server.host, config.server.port);
+      rows.push([
+        "Port available",
+        portFree ? "yes" : `no (${config.server.host}:${config.server.port} in use)`,
+      ]);
+      rows.push(["Scripts configured", String(config.scripts.length)]);
+      rows.push(["Auth enabled", String(config.auth.enabled)]);
+    } catch (error) {
+      if (error instanceof ConfigError) {
+        rows.push(["Config", error.message]);
+      } else {
+        throw error;
+      }
+    }
+  }
+
+  const labelWidth = Math.max(...rows.map(([label]) => label.length));
+  for (const [label, value] of rows) {
+    console.log(`${label.padEnd(labelWidth)}  ${value}`);
+  }
+}