install: fix alias/function parse collision and PS profile discovery

[BrettKinny]

Two regressions from the past ~2 days caused shell integration to break:

Bug 1 — Linux: bash syntax error at source time
Commit 646a589 switched from writing alias sqrbx='...' to writing shell
functions (sqrbx() { ... }), but _add_shell_func only guarded against
re-adding functions. Legacy alias lines from pre-646a589 installs stayed
in .bashrc, and when bash sourced the file interactively (expand_aliases
on), alias expansion happened at parse time — turning sqrbx() into
docker start -ai squarebox() and producing:

syntax error near unexpected token `('

Bug 2 — Windows: PowerShell profile never updated

• $LOCALAPPDATA/Microsoft/PowerShell/pwsh.exe was missing the /7/
  component, so the per-user install never got found.
• Microsoft Store install path was not checked.
• Commit 55f9183 gated every diagnostic behind --verbose, so a silent
  skip gave users zero feedback.
• The PS sqrbx-rebuild function invoked bare bash, which can resolve
  to WSL bash instead of Git Bash when launched from PowerShell.

Fix: managed block + dedicated sourced file

Mirror the Dockerfile pattern (~/.squarebox-*-aliases sourced from
~/.bashrc). install.sh now:

• Writes the four function bodies to ~/.squarebox-shell-init, overwritten
  unconditionally on every run (plus an inline unalias as belt-and-
  suspenders against any alias shadowing).
• Scrubs legacy content from $SHELL_RC via portable awk + mktemp + mv:
  removes any prior # >>> squarebox >>> block, legacy standalone
  alias sqrbx=... lines, and legacy one-liner function defs from the
  646a589-era writer.
• Appends a stable one-line sentinel block to $SHELL_RC that sources
  the init file.
• Runs bash -n $SHELL_RC after editing as a self-check so future
  regressions that break the rc file are caught at install time.
• Forces $SHELL_RC=$HOME/.bashrc when MSYSTEM is set so rebuilds
  launched from a parent PowerShell target the right file.

For PowerShell:

• Discovery order: command -v → where.exe pwsh → file probes covering
  Program Files/PowerShell/7, LOCALAPPDATA/Microsoft/PowerShell/7, and
  LOCALAPPDATA/Microsoft/WindowsApps.
• $PROFILE capture uses [Console]::Out.Write plus BOM + CR stripping
  to avoid trailing-newline and UTF-8 BOM contamination.
• Sanity-checks the returned profile path contains a Documents/PowerShell
  or Documents/WindowsPowerShell component before using it.
• Applies the same managed-block pattern (awk scrub + sentinel append)
  to the PS profile.
• PowerShell sqrbx-rebuild now explicitly resolves Git Bash at runtime
  (Program Files/Git/bin/bash.exe, with PATH fallback) so it never runs
  install.sh under WSL.
• Un-gates the "pwsh not found, skipping" message so Windows users
  always see feedback.

Also updates .github/workflows/e2e.yml 1.4 to exercise the real
managed-block logic from install.sh against a fixture containing the
exact legacy cruft that triggered Bug 1 — a permanent regression guard.

[Copilot]

Pull request overview

Fixes recent shell-integration regressions on Linux (bash alias/function parse collision) and Windows (PowerShell profile discovery/update not happening) by switching to a managed-block + dedicated init file approach and improving PowerShell detection/profile handling.

Changes:

• Writes shell functions into ~/.squarebox-shell-init and updates .bashrc/.zshrc via a scrubbed managed sentinel block, with a post-edit syntax check.
• Improves PowerShell (pwsh) discovery and profile update logic, and makes sqrbx-rebuild explicitly use Git Bash.
• Updates E2E workflow to validate the managed-block scrub/append logic against a legacy-cruft fixture.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 5 comments.

File	Description
install.sh	Reworks bash/zsh integration into a sourced init file + managed sentinel; improves PowerShell discovery and profile managed-block updates.
.github/workflows/e2e.yml	Extends E2E to run the real shell-integration block against a legacy .bashrc fixture and assert idempotency.

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[Copilot]

SQRBX_INIT is written under USER_HOME, but the sentinel added to $SHELL_RC sources "$HOME/.squarebox-shell-init". On Git Bash/MSYS2 where USER_HOME (derived from USERPROFILE) differs from HOME (/home/user), this will leave the init file unsourced and shell integration will not work. Make the init file path consistent (e.g., write it under $HOME, or have the sentinel source the USER_HOME location).

Suggested change

	cat >> "$SHELL_RC" <<'SQRBXRCEOF'
	# >>> squarebox >>>
	[ -f "$HOME/.squarebox-shell-init" ] && . "$HOME/.squarebox-shell-init"
	cat >> "$SHELL_RC" <<SQRBXRCEOF
	# >>> squarebox >>>
	[ -f "$SQRBX_INIT" ] && . "$SQRBX_INIT"

[Copilot]

The generated sqrbx-rebuild function runs "$HOME/squarebox/install.sh", but this script installs into "$INSTALL_DIR" which is based on USER_HOME (USERPROFILE on Windows). When HOME != USER_HOME (common in Git Bash), sqrbx-rebuild will point at a non-existent path. Consider emitting the resolved install.sh path (INSTALL_DIR/install.sh) into the init file, or computing it at runtime using USERPROFILE+cygpath.

Suggested change

	cat > "$SQRBX_INIT" <<'SQRBXEOF'
	# Managed by squarebox install.sh — overwritten on every install.
	# Drop any stale aliases with these names so they don't shadow the functions.
	unalias sqrbx squarebox sqrbx-rebuild squarebox-rebuild 2>/dev/null || true
	sqrbx() { if command -v winpty &>/dev/null && [[ -n "${MSYSTEM:-}" ]]; then winpty docker start -ai squarebox; else docker start -ai squarebox; fi; }
	squarebox() { sqrbx "$@"; }
	sqrbx-rebuild() { "$HOME/squarebox/install.sh" "$@"; }
	squarebox-rebuild() { sqrbx-rebuild "$@"; }
	cat > "$SQRBX_INIT" <<SQRBXEOF
	# Managed by squarebox install.sh — overwritten on every install.
	# Drop any stale aliases with these names so they don't shadow the functions.
	unalias sqrbx squarebox sqrbx-rebuild squarebox-rebuild 2>/dev/null || true
	sqrbx() { if command -v winpty &>/dev/null && [[ -n "\${MSYSTEM:-}" ]]; then winpty docker start -ai squarebox; else docker start -ai squarebox; fi; }
	squarebox() { sqrbx "\$@"; }
	sqrbx-rebuild() { "${INSTALL_DIR}/install.sh" "\$@"; }
	squarebox-rebuild() { sqrbx-rebuild "\$@"; }

[Copilot]

The self-check always runs bash -n "$SHELL_RC", but SHELL_RC can be ~/.zshrc when the user’s shell is zsh. Valid zshrc content may fail a bash syntax check and cause a misleading warning on every install. Consider gating this to bash rc files, or using the appropriate shell syntax check (e.g., zsh -n) when SHELL_RC is a zsh file.

Suggested change

	if ! bash -n "$SHELL_RC" 2>/dev/null; then
	echo "Warning: $SHELL_RC fails bash syntax check after edit — please inspect." >&2
	fi
	case "$SHELL_RC" in
	*.bashrc|*.bash_profile|*/.bashrc|*/.bash_profile)
	if ! bash -n "$SHELL_RC" 2>/dev/null; then
	echo "Warning: $SHELL_RC fails bash syntax check after edit — please inspect." >&2
	fi
	;;
	*.zshrc|*.zprofile|*/.zshrc|*/.zprofile)
	if command -v zsh >/dev/null 2>&1 && ! zsh -n "$SHELL_RC" 2>/dev/null; then
	echo "Warning: $SHELL_RC fails zsh syntax check after edit — please inspect." >&2
	fi
	;;
	esac

[Copilot]

The comment says the PowerShell profile sanity check should only accept paths under Documents/PowerShell or Documents/WindowsPowerShell, but the case pattern also allows */PowerShell/*, which is much broader and weakens the guard against bogus paths. Either tighten the allowed patterns to match the stated intent, or update the comment to reflect the broader acceptance criteria.

Suggested change

	*/Documents/PowerShell/*|*/Documents/WindowsPowerShell/*|*/PowerShell/*) ;;
	*/Documents/PowerShell/*|*/Documents/WindowsPowerShell/*) ;;

[Copilot]

The workflow fixture sets USER_HOME="$HOME", so it won’t catch regressions where USER_HOME and HOME differ (the exact scenario called out in install.sh for MSYS2/Git Bash). Consider setting USER_HOME to a different temp dir than HOME and asserting that the init file is written/sourced from the correct location, so the test would fail if these paths diverge again.