Add Claude Code project config and refine .gitignore

[JackieTien97]

Summary

Add Claude Code project-level configuration (CLAUDE.md, .claude/settings.json) and refine .gitignore to properly handle Claude Code generated files.

Changes

1. .gitignore — Refine Claude Code ignore rules

Before (too coarse):

.claude/
CLAUDE.md
.worktreeinclude

This ignored the entire .claude/ directory and CLAUDE.md, preventing any Claude Code config from being shared with the team.

After (fine-grained):

# Claude Code
.claude/settings.local.json
.claude/todos/
.claude/worktrees/
.claude/scheduled_tasks.json

Why ignore these specific files:

• .claude/settings.local.json — Machine-specific local settings (absolute paths, personal preferences). Committing this causes merge conflicts across different developer environments.
• .claude/todos/ — Session-level task tracking, ephemeral and per-session.
• .claude/worktrees/ — Temporary git worktree directories created during isolated development sessions.
• .claude/scheduled_tasks.json — Session-level scheduled/recurring tasks, not meaningful across sessions.

Why commit CLAUDE.md and .claude/settings.json:

• CLAUDE.md is the project instruction file — it tells Claude Code how to build, test, and format code in this project. Sharing it ensures all team members get consistent AI assistance.
• .claude/settings.json contains shared project hooks (e.g., auto-formatting). It should be committed so the whole team benefits from the same automated workflows.

2. CLAUDE.md — Project instructions for Claude Code

Comprehensive project guide covering:

• Project overview: IoTDB architecture, version info
• Build commands: Full build, per-module build, unit tests, single test class/method
• Integration tests: All profiles (tree-model, table-model, simple, cluster) with examples
• Code style: Spotless + Google Java Format, Checkstyle, import order
• Architecture: Node types (ConfigNode, DataNode, AINode), dual data model (tree/table), key subsystems (queryengine, storageengine, schemaengine, pipe, consensus), protocol layer, client libraries, API layer
• IDE setup: Generated source directories (Thrift, ANTLR)
• Common pitfalls: Missing Thrift compiler workaround, pre-existing compilation errors, Spotless formatting discipline, Gson compatibility
• Git commit: No Co-Authored-By trailer in commit messages

3. .claude/settings.json — Shared project hooks

Configures a PostToolUse hook that automatically runs mvn spotless:apply on Java files after Claude Code writes or edits them. This ensures all AI-generated code changes comply with the project's Spotless formatting rules without manual intervention.

{
  "hooks": {
    "PostToolUse": [{
      "matcher": "Write|Edit",
      "hooks": [{
        "type": "command",
        "command": "...(spotless:apply on .java files only)...",
        "timeout": 30,
        "statusMessage": "Running spotless format..."
      }]
    }]
  }
}

Test plan

• Verify .gitignore correctly ignores local files (settings.local.json, todos/, worktrees/, scheduled_tasks.json)
• Verify CLAUDE.md and .claude/settings.json are tracked by git
• Verify the PostToolUse hook triggers mvn spotless:apply when editing .java files
• Verify the hook skips non-Java files

[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

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 39.82%. Comparing base (1c1cbca) to head (0cdf3a8).

Additional details and impacted files

@@             Coverage Diff              @@
##             master   #17458      +/-   ##
============================================
- Coverage     39.82%   39.82%   -0.01%     
  Complexity      312      312              
============================================
  Files          5135     5135              
  Lines        347073   347073              
  Branches      44220    44220              
============================================
- Hits         138221   138211      -10     
- Misses       208852   208862      +10     

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