feat: reuse Chrome profile login state via --profile <name> (#1131)

* feat(chrome): add Chrome profile name resolution and copy for --profile flag

When --profile receives a name without path separators (e.g., "Default"),
it now resolves the name against installed Chrome profiles, copies the
profile to a temp directory (excluding large cache dirs), and launches
Chrome with the copied profile to reuse login state.

Key changes:
- Add profile resolution: is_chrome_profile_name, find_chrome_user_data_dir,
  list_chrome_profiles, resolve_chrome_profile (3-tier matching)
- Add copy_chrome_profile with best-effort copy and exclusion list
- Wire preprocessing into launch_chrome before retry loop
- Add use_real_keychain field to LaunchOptions for conditional keychain flags
- Make --password-store=basic and --use-mock-keychain conditional

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

* feat(cli): add `profiles` command to list available Chrome profiles

Adds `agent-browser profiles` command that reads Chrome's Local State
file to list available profiles with directory names and display names.
Supports --json output. Added help text in print_command_help and
print_help.

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

* docs: add Chrome profile reuse documentation across all locations

Update all 5 documentation locations per AGENTS.md:
- output.rs: updated --profile help text and examples
- README.md: added Chrome Profile Reuse section, updated options table
- SKILL.md: added profile reuse as Option 2
- docs/src/app/sessions/page.mdx: added Chrome profile reuse section
- chrome.rs: added doc comments to get_chrome_user_data_dirs

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

* style: fix formatting and clippy warning in chrome.rs

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

* refactor: simplify profile resolution and launch integration

- Only clone LaunchOptions when profile name requires resolution
  (avoids unnecessary allocation on every Chrome launch)
- Remove redundant is_file() check before copy of Local State
  (copy() handles missing files naturally)
- Extract format_profile_list() to deduplicate error formatting
- Remove unnecessary section comments in tests

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

* refactor(tests): use RAII TempDir guard for test cleanup

Replace manual remove_dir_all calls with a TempDir struct that
auto-cleans on drop, preventing temp dir leaks on test panics.

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

---------

Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Co-authored-by: ctate <366502+ctate@users.noreply.github.com>

docs/src/app/sessions/page.mdx

@@ -30,9 +30,40 @@ Each session has its own:
 - Navigation history
 - Authentication state
 
+## Chrome profile reuse
+
+The simplest way to reuse your existing login state: pass a Chrome profile name to `--profile`. agent-browser copies the profile to a temp directory (read-only snapshot) and launches Chrome with your existing cookies and sessions.
+
+```bash
+# List available Chrome profiles
+agent-browser profiles
+
+# Reuse your default Chrome profile's login state
+agent-browser --profile Default open https://gmail.com
+
+# Use a named profile (by display name or directory name)
+agent-browser --profile "Work" open https://app.example.com
+
+# Or via environment variable
+AGENT_BROWSER_PROFILE=Default agent-browser open https://gmail.com
+```
+
+<table>
+  <thead>
+    <tr><th>Detail</th><th>Description</th></tr>
+  </thead>
+  <tbody>
+    <tr><td>Supported browsers</td><td>Chrome, Chrome Canary, Chromium, Brave</td></tr>
+    <tr><td>What's copied</td><td>Cookies, local storage, extensions state (cache dirs excluded for speed)</td></tr>
+    <tr><td>Original profile</td><td>Never modified (read-only snapshot)</td></tr>
+    <tr><td>Cleanup</td><td>Temp copy deleted when browser closes</td></tr>
+    <tr><td>Windows note</td><td>Close Chrome before using <code>--profile &lt;name&gt;</code> if Chrome is running</td></tr>
+  </tbody>
+</table>
+
 ## Persistent profiles
 
-By default, browser state is lost when the browser closes. Use `--profile` to persist state across restarts:
+For a custom profile directory that persists state across browser restarts, pass a path to `--profile`:
 
 ```bash
 # Use a persistent profile directory