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

cli/src/native/cdp/chrome.rs

@@ -219,9 +219,18 @@ fn build_chrome_args(options: &LaunchOptions) -> Result<ChromeArgs, String> {
 pub fn launch_chrome(options: &LaunchOptions) -> Result<ChromeProcess, String> {
     let chrome_path = match &options.executable_path {
         Some(p) => PathBuf::from(p),
-        None => {
-            find_chrome().ok_or("Chrome not found. Run `agent-browser install` to download Chrome, or use --executable-path.")?
-        }
+        None => find_chrome().ok_or_else(|| {
+            let cache_dir = crate::install::get_browsers_dir();
+            format!(
+                "Chrome not found. Checked:\n  \
+                 - agent-browser cache: {}\n  \
+                 - System Chrome installations\n  \
+                 - Puppeteer browser cache\n  \
+                 - Playwright browser cache\n\
+                 Run `agent-browser install` to download Chrome, or use --executable-path.",
+                cache_dir.display()
+            )
+        })?,
     };
 
     let max_attempts = 3;
@@ -438,6 +447,18 @@ pub fn find_chrome() -> Option<PathBuf> {
         return Some(p);
     }
 
+    // If the cache directory exists but no Chrome was found, warn -- this
+    // likely means the cache is corrupted or the directory layout is unexpected.
+    let cache_dir = crate::install::get_browsers_dir();
+    if cache_dir.exists() {
+        let _ = writeln!(
+            std::io::stderr(),
+            "Warning: Chrome cache directory exists ({}) but no Chrome binary found inside. \
+             Falling back to system Chrome. Run `agent-browser install` to re-download.",
+            cache_dir.display()
+        );
+    }
+
     // 2. Check system-installed Chrome
     #[cfg(target_os = "macos")]
     {
@@ -502,7 +523,10 @@ pub fn find_chrome() -> Option<PathBuf> {
         }
     }
 
-    // 3. Fallback: check Playwright's browser cache (for existing installs)
+    // 3. Fallback: check Puppeteer / Playwright browser caches
+    if let Some(p) = find_puppeteer_chrome() {
+        return Some(p);
+    }
     if let Some(p) = find_playwright_chromium() {
         return Some(p);
     }
@@ -684,6 +708,76 @@ fn should_disable_dev_shm(existing_args: &[String]) -> bool {
     false
 }
 
+/// Search Puppeteer's browser cache for a Chrome binary.
+/// Puppeteer v19+ stores Chrome in ~/.cache/puppeteer/chrome/<platform>-<version>/
+fn find_puppeteer_chrome() -> Option<PathBuf> {
+    let mut search_dirs = Vec::new();
+
+    if let Ok(custom) = std::env::var("PUPPETEER_CACHE_DIR") {
+        search_dirs.push(PathBuf::from(custom).join("chrome"));
+    }
+
+    if let Some(home) = dirs::home_dir() {
+        search_dirs.push(home.join(".cache/puppeteer/chrome"));
+    }
+
+    for dir in &search_dirs {
+        if !dir.is_dir() {
+            continue;
+        }
+        if let Ok(entries) = std::fs::read_dir(dir) {
+            let mut matches: Vec<PathBuf> = entries
+                .filter_map(|e| e.ok())
+                .filter(|e| e.path().is_dir())
+                .filter_map(|e| {
+                    let candidate = build_puppeteer_binary_path(&e.path());
+                    if candidate.exists() {
+                        Some(candidate)
+                    } else {
+                        None
+                    }
+                })
+                .collect();
+            matches.sort();
+            matches.reverse();
+            if let Some(p) = matches.into_iter().next() {
+                return Some(p);
+            }
+        }
+    }
+
+    None
+}
+
+#[cfg(target_os = "linux")]
+fn build_puppeteer_binary_path(version_dir: &Path) -> PathBuf {
+    version_dir.join("chrome-linux64/chrome")
+}
+
+#[cfg(target_os = "macos")]
+fn build_puppeteer_binary_path(version_dir: &Path) -> PathBuf {
+    // Puppeteer uses chrome-mac-arm64 or chrome-mac-x64 depending on arch
+    let arm = version_dir.join(
+        "chrome-mac-arm64/Google Chrome for Testing.app/Contents/MacOS/Google Chrome for Testing",
+    );
+    if arm.exists() {
+        return arm;
+    }
+    version_dir.join(
+        "chrome-mac-x64/Google Chrome for Testing.app/Contents/MacOS/Google Chrome for Testing",
+    )
+}
+
+#[cfg(target_os = "windows")]
+fn build_puppeteer_binary_path(version_dir: &Path) -> PathBuf {
+    version_dir.join(r"chrome-win64\chrome.exe")
+}
+
+#[cfg(not(any(target_os = "macos", target_os = "linux", target_os = "windows")))]
+fn build_puppeteer_binary_path(version_dir: &Path) -> PathBuf {
+    version_dir.join("chrome")
+}
+
 /// Search Playwright's browser cache for a Chromium binary.
 /// Legacy fallback for users who previously installed Chromium via Playwright.
 fn find_playwright_chromium() -> Option<PathBuf> {