Upgrade to Casbin v3.9.0

[Copilot]

Upgrades Casbin dependency from v2.66.1 to v3.9.0 to include latest bug fixes.

Changes

Dependencies:

• github.com/casbin/casbin/v2 → v3 v3.9.0
• Updated import paths across codebase (watcher.go, watcher_test.go, README.md)

API Breaking Change:

• GetPolicy() now returns ([][]string, error) instead of [][]string
• Updated test assertions to capture error return value:

// Before (v2)
if !reflect.DeepEqual(e2.GetPolicy(), e.GetPolicy()) {
    // ...
}

// After (v3)
e2Policy, _ := e2.GetPolicy()
ePolicy, _ := e.GetPolicy()
if !reflect.DeepEqual(e2Policy, ePolicy) {
    // ...
}

Transitive Updates:

• github.com/Knetic/govaluate → github.com/casbin/govaluate v1.3.0
• github.com/google/uuid v1.3.0 → v1.6.0
• Added github.com/bmatcuk/doublestar/v4 v4.6.1

Warning

Firewall rules blocked me from connecting to one or more addresses (expand for details)

I tried to connect to the following addresses, but was blocked by firewall rules:

• go.googlesource.com
  • Triggering command: /update-job-proxy /update-job-proxy (dns block)
• https://api.github.com/repos/casbin/casbin/releases/tags/v3.0.0
  • Triggering command: /usr/bin/curl curl -s REDACTED (http block)

If you need me to access, download, or install something from one of these locations, you can either:

• Configure Actions setup steps to set up my environment, which run before the firewall is enabled
• Add the appropriate URLs or hosts to the custom allowlist in this repository's Copilot coding agent settings (admins only)

Original prompt

---

This section details on the original issue you should resolve

<issue_title>Upgrade to Casbin v3</issue_title>
<issue_description>Could we upgrade to Casbin v3 to include the latest bug fixes?

For example: apache/casbin#1656

the latest Casbin version is: https://github.com/casbin/casbin/releases/tag/v3.9.0</issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes Upgrade to Casbin v3 #54

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