fix(terminal): avoid treating WSL bash as Git Bash

[SpencerJung]

Closes #57

Summary

• Detect Git Bash on Windows only from Git-for-Windows install paths such as Git/bin/bash.exe or Git/usr/bin/bash.exe.
• Stop advertising a generic bash.exe as Git Bash when it resolves to the Windows WSL launcher.
• When a bash.exe launch request is not a Git Bash executable, redirect it to the resolved Git Bash executable if one is installed.

Issue Evidence

• On this Windows host, where.exe bash.exe resolves C:\Windows\System32\bash.exe and C:\Users\theni\AppData\Local\Microsoft\WindowsApps\bash.exe.
• Those executables are WSL launchers, which matches the issue output: wsl: ... execvpe(/bin/bash) failed.
• Root cause: SideX labeled whichever bash.exe appeared on PATH as Git Bash.

Verification

• where.exe bash.exe — confirmed WSL launcher paths are first on PATH in this environment.
• git diff --check — passed.
• rust-analyzer LSP — blocked: rust-analyzer is not installed in this workflow shell.
• Rust compile/fmt checks — blocked per repository profile because cargo and rustc are not installed in this workflow shell.

Community Rules Review

• Focused PR for a single issue/concern.
• Followed existing Rust terminal command patterns.
• No unauthorized version bump.
• No workflow/tracker/profile files included in the target repo diff.