chore: add bin/ci for pre-push linter + unit tests

Auto-fixes lint errors but still fails so you review and re-commit.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: pftg

README.md

@@ -120,7 +120,7 @@ See [Configuration Reference](docs/configuration.md) for all options.
 
 **Screenshots differ between CI and local** — Use `tolerance: 0.001` or `perceptual_threshold: 2.0`. Set `window_size` for consistent dimensions.
 
-**Animations cause flaky diffs** — `Capybara.disable_animation = true`, or `stability_time_limit: 1`.
+**Animations cause flaky diffs** — `Capybara::Screenshot.disable_animations = true` disables CSS animations/transitions before each screenshot. Or use `stability_time_limit: 1` to wait for animations to finish.
 
 **Dynamic content always differs** — `screenshot "page", skip_area: [".timestamp", "#ad-banner"]`
 

bin/ci

@@ -0,0 +1,13 @@
+#!/bin/bash
+set -e
+
+echo "Running linter..."
+if ! bin/standardrb; then
+  echo "Lint errors found. Auto-fixing..."
+  bin/standardrb -a
+  echo "Lint errors were auto-fixed. Please review and re-commit."
+  exit 1
+fi
+
+echo "Running unit tests..."
+bin/rake test:unit