Stop profile aliases from shadowing built-in commands

[26zl]

Why (draft: PowerShell runtime behavior not fully verifiable here)

The profile called Remove-Alias on the built-in gc, ls, and cat aliases and then redefined them. Because the alias table is shared across the whole session, this replaced Get-Content / Get-ChildItem for every script run afterward (e.g. a script at the prompt doing gc config.json or cat x), not just the interactive prompt.

Changes

• gc -> gcmsg: rename the git-commit helper and remove Remove-Alias gc, so the built-in gc (Get-Content) stays intact.
• ls: drop the Remove-Alias ls + function ls; keep eza under la / ll / lt (which do not collide with a built-in alias). ls stays Get-ChildItem.
• cat: drop the Remove-Alias cat + function cat; expose bat as bcat. cat stays Get-Content.
• ssh wrapper: now resolves the host's effective config with ssh -G <host> and adds ConnectTimeout / ServerAliveInterval / ServerAliveCountMax only where neither the command line nor ~/.ssh/config already set them (ssh -G reports unset ConnectTimeout as none, unset ServerAliveInterval as 0). Previously it keyed only off the command line and would override values from ~/.ssh/config.
• Correct the inaccurate gpush / gpull comments (they claimed to remove gp/gl aliases and misnamed the built-ins).
• Update Show-Help text, the command registry, README alias tables, and the gc test call sites (tests/test.ps1, tests/ci-functional.ps1) to match.

Findings / rationale

• Any session-scoped override of these names affects later scripts regardless of alias-vs-function precedence, so the only safe fix is to not bind the modern tools to the built-in names. Chose distinct names (per the review's first option) over an opt-in flag to keep the change minimal and safe-by-default.
• In CI (Windows, no eza/bat) the ls/cat probes already exercised the built-ins, so they stay valid; gcmsg is defined unconditionally.

Verification

• Parser::ParseFile clean on profile, tests/test.ps1, tests/ci-functional.ps1.
• PSScriptAnalyzer (CI exclude set) on the profile: 0 findings.
• Unverified here: runtime behavior of the ssh wrapper (needs a Windows ssh.exe + an interactive session for the tab-title path); bcat only exists when bat is installed. No workflows touched.