fix(harness): auto-inject ALLOW rules for plan mode tools

[Buktal]

AgentScope-Java Version

2.0.0-SNAPSHOT

Description

Problem:
Issue #1910 reported that PlanModeMiddleware whitelist and PermissionEngine were not coordinated. When enablePlanMode(true) is called, plan_enter, plan_write, and todo_write are in PlanModeMiddleware.ALWAYS_ALLOWED (execution-layer whitelist), but PermissionEngine still prompts ASK in DEFAULT mode because it has no awareness of plan mode context.

Root Cause:

• PlanModeMiddleware controls onActing phase (execution gate)
• PermissionEngine controls onReasoning phase (permission prompt)
• They operate independently with no coordination

Solution:
When HarnessAgent.Builder.enablePlanMode(true) is called, automatically inject unconditional ALLOW rules for plan_enter, plan_write, and todo_write into PermissionContextState. plan_exit is deliberately excluded to preserve HITL (Human-in-the-Loop) confirmation semantics.

Changes:

1. Add permissionContext mirror field in HarnessAgent.Builder (default: empty context)
2. Modify permissionContext() setter to store locally instead of forwarding to inner immediately
3. In build(): when planModeEnabled = true, merge user context + plan mode allow rules, then call inner.permissionContext() once
4. When planModeEnabled = false, directly forward user context to inner (behavior unchanged)
5. Add 6 tests verifying auto-injection behavior

Testing:

• 6 new tests in HarnessAgentPlanModePermissionTest:
  • plan_enter / plan_write / todo_write get ALLOW rules ✅
  • plan_exit has no ALLOW rule (preserves ASK) ✅
  • User-configured rules are preserved ✅
  • No injection when plan mode disabled ✅
• All 590 existing tests pass (Failures: 0)

Backward Compatibility:

• planModeEnabled = false (default): behavior unchanged
• User-configured permission rules are preserved and merged
• User ASK rules take precedence over auto-injected ALLOW rules (PermissionEngine evaluation order)

Fixes #1910

Checklist

• Code has been formatted with mvn spotless:apply
• All tests are passing (590 tests, 0 failures)
• Javadoc comments are complete
• Documentation updated (inline comments explain the coordination)
• Code is ready for review

[codecov]

Codecov Report

❌ Patch coverage is 94.44444% with 1 line in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
...java/io/agentscope/harness/agent/HarnessAgent.java	94.44%	0 Missing and 1 partial ⚠️

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