fix: Windows Chrome extraction and debugging environment (#1088)

* windows debugging

* fixes

* fixes

* fix: handle Windows path separators in Chrome zip extraction

The zip crate's enclosed_name() normalizes paths to use backslashes on
Windows, but extract_zip used split_once('/') which only matches forward
slashes. This caused Chrome to be extracted into a nested chrome-win64/
subdirectory instead of directly into the version directory.

Also adds debug diagnostics to find_installed_chrome() (gated behind
AGENT_BROWSER_DEBUG) and better error messages when Chrome cache exists
but no binary is found.

Fixes #1076

* feat: add Puppeteer browser cache as Chrome fallback

Search ~/.cache/puppeteer/chrome/ (or PUPPETEER_CACHE_DIR) for Chrome
binaries before falling back to Playwright's cache. Puppeteer v19+
stores Chrome for Testing in this location, so users with an existing
Puppeteer install can use agent-browser without a separate install step.

* fmt

scripts/windows-debug/stop.sh

@@ -0,0 +1,28 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd)"
+INSTANCE_FILE="$SCRIPT_DIR/.instance"
+
+if [[ ! -f "$INSTANCE_FILE" ]]; then
+  echo "Error: No instance provisioned. Nothing to stop."
+  exit 1
+fi
+
+source "$INSTANCE_FILE"
+export AWS_DEFAULT_REGION="$REGION"
+
+STATE=$(aws ec2 describe-instances \
+  --instance-ids "$INSTANCE_ID" \
+  --query "Reservations[0].Instances[0].State.Name" --output text)
+
+if [[ "$STATE" == "stopped" ]]; then
+  echo "Instance $INSTANCE_ID is already stopped."
+  exit 0
+fi
+
+echo "Stopping instance $INSTANCE_ID..."
+aws ec2 stop-instances --instance-ids "$INSTANCE_ID" --no-cli-pager
+echo "Waiting for stopped state..."
+aws ec2 wait instance-stopped --instance-ids "$INSTANCE_ID"
+echo "Instance stopped. No compute charges while stopped (storage only: ~$0.64/mo)."