feat(cli): wmill init creates root .claude/launch.json for the picker

Adds a workspace-root .claude/launch.json so Claude Code can launch
`wmill dev` from the project root and land on the file picker (no
--path → picker mode). Per-flow and per-raw_app launch.json files are
already generated by the existing scans. Skipped (with a gray log) if
the file already exists, so the user's customizations are preserved.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

cli/src/commands/init/init.ts

@@ -1,6 +1,6 @@
 import { stat, writeFile, rm, readdir } from "node:fs/promises";
 import { join } from "node:path";
-import { writeFileSync, mkdirSync } from "node:fs";
+import { writeFileSync, mkdirSync, existsSync } from "node:fs";
 import { colors } from "@cliffy/ansi/colors";
 import { Command } from "@cliffy/command";
 import { Confirm } from "@cliffy/prompt/confirm";
@@ -274,6 +274,34 @@ async function initAction(opts: InitOptions) {
     }
   }
 
+  // Generate .claude/launch.json at the workspace root so Claude Code can launch
+  // `wmill dev` from there and land on the file picker (no --path → picker mode).
+  try {
+    const rootClaudeDir = join(".", ".claude");
+    const rootLaunchPath = join(rootClaudeDir, "launch.json");
+    if (existsSync(rootLaunchPath)) {
+      log.info(colors.gray(`Skipped ${rootLaunchPath} (already exists)`));
+    } else {
+      const rootLaunchJson = JSON.stringify({
+        version: "0.0.1",
+        configurations: [{
+          name: "windmill",
+          runtimeExecutable: "bash",
+          runtimeArgs: ["-c", "wmill dev --proxy-port ${PORT:-4000} --no-open"],
+          port: 4000,
+          autoPort: true,
+        }],
+      }, null, 2) + "\n";
+      mkdirSync(rootClaudeDir, { recursive: true });
+      writeFileSync(rootLaunchPath, rootLaunchJson, "utf-8");
+      log.info(colors.green(`Created ${rootLaunchPath}`));
+    }
+  } catch (error) {
+    log.warn(
+      `Could not create root .claude/launch.json: ${error instanceof Error ? error.message : error}`
+    );
+  }
+
   // Generate .claude/launch.json for each flow folder
   try {
     const flowSuffix = nonDottedPaths ? "__flow" : ".flow";