GPUI: t3code chat buttons do not start chat on Windows

[maddada]

Environment

• GPUI app
• Windows

Problem

Chat (t3code) does not start from either of these entry points:

• The chat icon in the Agents tab bar.
• The chat button in a project heading in the sidebar.

Expected behavior

Clicking either chat button should start a t3code chat in the relevant project/session context.

[maddada]

Applied fix in the working tree.

• Both the Agents-tab chat icon and project-heading chat action now converge on the same Windows/WSL T3 creation path and preserve the clicked pane context across async creation.
• Windows uses secure BCrypt UUID generation.
• The selected WSL distro owns the T3 Node runtime, entrypoint, authentication state, and supervisor launch; no host/dev fallback is used.
• Windows release packaging now includes and validates the architecture-matching T3 runtime for x64/ARM64.
• WSL supervision uses /bin/sh; macOS and non-WSL Linux behavior remains unchanged.

Final static verifier: PASS.

Per request, no tests, builds, app launch, commit, or push were performed.