install.sh: Alacritty from its release DMG, under a stated rule

Homebrew disabled the alacritty cask on 2026-09-01: upstream builds are ad-hoc
signed and not notarized. Existing installs kept it, but a new Mac got no
Alacritty, and this repo's config, Dock, Hammerspoon and terminal-set-opacity
all assume one.

Clearing a quarantine flag is now allowed under one rule instead of never: the
file is pinned by a hash reviewed here, its signature verifies as unmodified,
and the app is named explicitly. Alacritty passes -- the v0.17.0 DMG matches
GitHub's published digest, and codesign --verify --deep --strict passes.
toggleMute failed on the signature, which is why it stays dropped. The hash is
hard-coded rather than looked up, since a checksum fetched beside the file
catches corruption, not substitution.

The filed version wrapped the steps in `( set -euo pipefail ... ) || warn`,
and bash ignores set -e on the left of ||: a wrong hash still installed the
app. Each step now exits by hand. Tested against a scratch target with the
right hash, a wrong hash, and a failing signature check.

From change request 56fc45.

1 files changed, 2 insertions, 1 deletions

diff --git a/Brewfile b/Brewfile
index eac03d9..6f3f465 100644
--- a/Brewfile
+++ b/Brewfile
@@ -34,7 +34,8 @@ brew "tree-sitter-cli"     # nvim-treesitter generates and compiles parsers with
 # Wanted on any machine this account uses, though nothing here reads them.
 brew "glow"                # markdown rendered in the terminal
 
-cask "alacritty"
+# Not alacritty: Homebrew disabled that cask on 2026-09-01 (it fails the
+# Gatekeeper check), so install.sh installs it from the release DMG, pinned.
 cask "hammerspoon"
 cask "neovide-app"
 # Wanted on any Mac this account uses, though nothing here depends on it.