feat: add session manager and update README

[bugoutianzhen123]

Fix: #1

Added SessionManager to handle sessions and their lifecycle.
Added README content to explain and demonstrate continuous authorization usage.

These additions introduce robust session management and guide users on using continuous authorization.

[Copilot]

Pull Request Overview

This PR adds a robust session management system and comprehensive documentation to the casbin-ucon project. The changes introduce a dedicated SessionManager class to handle session lifecycle operations and provide detailed README content explaining continuous authorization behavior.

• Introduces SessionManager with thread-safe session operations and dedicated Session struct
• Updates the UconEnforcer to use the new session management system
• Adds comprehensive README documentation with usage examples and continuous authorization guidelines

Reviewed Changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
session.go	New file implementing Session struct and SessionManager with thread-safe operations
ucon_enforcer.go	Refactored to use SessionManager instead of direct map operations
ucon_enforcer_interface.go	Updated EnforceWithSession return type from bool to *Session
ucon_enforcer_test.go	Updated tests to work with new Session API methods
ucon_enforcer_b_test.go	Added placeholder benchmark file
README.md	Added comprehensive documentation with usage examples and behavior explanations

Comments suppressed due to low confidence (1)

ucon_enforcer_test.go:1

• The comment 'reused' should be 'refused' to match the context of session denial.

// Copyright 2025 The casbin Authors. All Rights Reserved.

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[Copilot]

Pull Request Overview

Copilot reviewed 6 out of 6 changed files in this pull request and generated 2 comments.

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[Copilot]

Pull Request Overview

Copilot reviewed 6 out of 6 changed files in this pull request and generated 3 comments.

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[Copilot]

The error variable 'err' is being used in the error message but 'err' could be nil at this point. The test should use a more appropriate message like 'Expected session to be nil after revocation, but got non-nil session'.

Suggested change

	t.Fatalf("session revocation failed: %v", err)
	t.Fatalf("Expected session to be nil after revocation, but got non-nil session")

[Copilot]

When session is nil, err might also be nil (based on the EnforceWithSession implementation), which would result in 'Failed to enforce: '. The error message should handle this case properly or check err separately.

[Copilot]

Same issue as Comment 3 - when session is nil, err might also be nil, leading to an unhelpful error message. The error handling should be improved to provide meaningful feedback.

Suggested change

	t.Fatalf("Failed to enforce: %v", err)
	if err == nil {
	t.Fatalf("Failed to enforce: session and error are both nil, unexpected state")
	} else {
	t.Fatalf("Failed to enforce: %v", err)
	}

[github-actions]

🎉 This PR is included in version 1.1.0 🎉

The release is available on GitHub release

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