Handle gpui input placeholder API change in accounts view

[Codex]

Recent gpui update requires set_placeholder to receive window and Context, and set_default_value was replaced. This broke cargo clippy with E0061/E0599 in account input setup.

• Input placeholders: pass window and per-update cx when setting placeholders for AK/SK/region fields across providers.
• Region defaults: use set_value to seed default regions (AWS us-east-1, Aliyun cn-hangzhou) since set_default_value no longer exists.

Example:

self.region_input.update(cx, |state, cx| {
    state.set_placeholder("Region (optional, default us-east-1)", window, cx);
    state.set_value("us-east-1", window, cx);
});

Warning

Firewall rules blocked me from connecting to one or more addresses (expand for details)

I tried to connect to the following addresses, but was blocked by firewall rules:

• docs.rs
  • Triggering command: /usr/bin/curl curl -L REDACTED git conf�� get --global odules/@openai/c.*[0-9]\.[0-9] st;localhost:*;1dirname (dns block)
  • Triggering command: /usr/bin/curl curl -L REDACTED dirname /hom�� gpui-component/0.5.0-preview2/download git ndor/bin/lsb_release get --global /opt/pipx_bin/git sed k/_t�� s/^\([0-9]\)/v\1/g $0; sep=RS } /opt/hostedtoolcache/node/24.14.0/x64/lib/node_modules/@openai/codex/vendor/x86_64-REDACTED-linux-musl/path/lsb_release -b codex/format-cod-e (dns block)

If you need me to access, download, or install something from one of these locations, you can either:

• Configure Actions setup steps to set up my environment, which run before the firewall is enabled
• Add the appropriate URLs or hosts to the custom allowlist in this repository's Copilot coding agent settings (admins only)