docs: streamline agent conventions and add workflow constraints

[rawvoid]

Summary of Changes

This PR updates AGENTS.md to streamline agent conventions and establish clear workflow boundaries:

1. Workflow & Planning:

   • Added explicit plan requirement (Plan First) and task breakdown (Task Breakdown) for complex tasks.
   • Added strict user approval gate (Approval Gate) requiring explicit user approval on plans before code implementation starts.

2. Code & Research:

   • Added preference for inspecting local Maven repository (~/.m2/repository) source JARs and using mvn dependency:sources over web search (Local Source Inspection).
   • Standardized Java 21+ usage, code hygiene, and English-only comments/Javadoc.
   • Removed framework-specific XJC rules.

3. Testing & Verification:

   • Mandatory execution of minimal test suite (mvn test).
   • Strict prohibition against deleting failing tests or commenting out assertions.

4. Git & Remote Actions:

   • Enforced fine-grained, atomic local commits (Atomic Local Commits) and accurate commit messages (Accurate Commit Messages).

5. Communication:

   • Standardized user interaction language matching user prompt language while keeping PRs, commits, comments, and Javadoc in English.

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud