Revert "Build webui/ as part of cargo build (ArroyoSystems#1008)" (ArroyoSystems#1015)

This reverts commit a1dd91a.

Author: QnJ1c2kNCg

crates/arroyo-api/build.rs

@@ -1,77 +1,7 @@
 use cornucopia::{CodegenSettings, Error};
 use postgres::{Client, NoTls};
-use std::path::PathBuf;
-use std::process::Command;
-
-fn ensure_webui_built() {
-    let manifest_dir = PathBuf::from(std::env::var("CARGO_MANIFEST_DIR").unwrap());
-    let webui_dir = manifest_dir.join("../../webui");
-    let dist_index = webui_dir.join("dist/index.html");
-
-    // Only re-run this build script when dist/ changes (or is created).
-    // We intentionally do NOT track webui/src/ here — the webui has its own
-    // build toolchain. Developers who modify the frontend should run
-    // `pnpm build` in webui/ themselves; this block only bootstraps
-    // an initial build so that `cargo build` works out of the box.
-    println!(
-        "cargo:rerun-if-changed={}",
-        webui_dir.join("dist").display()
-    );
-
-    if dist_index.exists() {
-        return;
-    }
-
-    eprintln!("webui/dist not found — building the web UI...");
-
-    // Verify pnpm is available
-    let pnpm = Command::new("pnpm").arg("--version").output();
-    if pnpm.is_err() || !pnpm.unwrap().status.success() {
-        panic!(
-            "\n\n\
-            ========================================================\n\
-            pnpm is required to build the Arroyo web UI but was not\n\
-            found on $PATH.\n\
-            ========================================================\n"
-        );
-    }
-
-    // Install dependencies (frozen so the lockfile is never mutated by a Rust build)
-    let install = Command::new("pnpm")
-        .args(["install", "--frozen-lockfile"])
-        .current_dir(&webui_dir)
-        .status()
-        .expect("failed to spawn `pnpm install`");
-
-    if !install.success() {
-        panic!("pnpm install failed in webui/ — see output above");
-    }
-
-    // Build the frontend
-    let build = Command::new("pnpm")
-        .arg("build")
-        .current_dir(&webui_dir)
-        .status()
-        .expect("failed to spawn `pnpm build`");
-
-    if !build.success() {
-        panic!("pnpm build failed in webui/ — see output above");
-    }
-
-    // Sanity check
-    if !dist_index.exists() {
-        panic!(
-            "pnpm build succeeded but webui/dist/index.html was not created. \
-             Check the vite config in webui/."
-        );
-    }
-
-    eprintln!("webui built successfully.");
-}
 
 fn main() -> Result<(), Error> {
-    ensure_webui_built();
-
     let queries_path = "queries";
     let destination = format!("{}/api-sql.rs", std::env::var("OUT_DIR").unwrap());
     let settings = CodegenSettings {