refactor(skill): remove snakeyaml dependency with lightweight YAML parser

[fang-tech]

AgentScope-Java Version

1.0.7-SNAPSHOT

Description

Summary

Remove the snakeyaml dependency by implementing a lightweight YAML parser for frontmatter parsing.

Changes

• MarkdownSkillParser: Add SimpleYamlParser inner class supporting:

  • Simple key: value format parsing
  • Single/double quoted string values
  • Comment lines (#) skipping
  • Escape sequence handling

• Type Change: Map<String, Object> → Map<String, String> for metadata

• Updated Files:

  • MarkdownSkillParser.java
  • SkillUtil.java
  • FileSystemSkillRepository.java
  • MarkdownSkillParserTest.java

• Removed: snakeyaml dependency from agentscope-core/pom.xml

Breaking Changes

• Nested YAML structures no longer supported (only flat key-value pairs)
• ParsedMarkdown.getMetadata() returns Map<String, String> instead of Map<String, Object>

Checklist

Please check the following items before code is ready to be reviewed.

• Code has been formatted with mvn spotless:apply
• All tests are passing (mvn test)
• Javadoc comments are complete and follow project conventions
• Related documentation has been updated (e.g. links, examples, etc.)
• Code is ready for review

[Copilot]

Pull request overview

This PR removes the snakeyaml dependency by implementing a lightweight custom YAML parser (SimpleYamlParser) for parsing frontmatter in markdown skill files. The change simplifies the dependency footprint and restricts YAML support to flat key-value pairs with string values only.

Changes:

• Implemented SimpleYamlParser inner class with support for simple key-value parsing, quoted strings, escape sequences, and comment handling
• Changed metadata type from Map<String, Object> to Map<String, String> throughout the codebase
• Removed snakeyaml dependency from agentscope-core/pom.xml

Reviewed changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 14 comments.

Show a summary per file

File	Description
agentscope-core/pom.xml	Removed snakeyaml dependency
agentscope-core/src/main/java/io/agentscope/core/skill/util/MarkdownSkillParser.java	Added SimpleYamlParser inner class with parsing/generation methods; updated ParsedMarkdown to use Map<String, String>
agentscope-core/src/main/java/io/agentscope/core/skill/util/SkillUtil.java	Simplified metadata handling due to type change from Map<String, Object> to Map<String, String>
agentscope-core/src/main/java/io/agentscope/core/skill/repository/FileSystemSkillRepository.java	Updated metadata map type declaration
agentscope-core/src/test/java/io/agentscope/core/skill/util/MarkdownSkillParserTest.java	Removed nested YAML tests; added tests for quoted values, comments, and values with colons; updated test assertions for new type

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

[codecov]

Codecov Report

❌ Patch coverage is 76.57658% with 26 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
...gentscope/core/skill/util/MarkdownSkillParser.java	75.23%	12 Missing and 14 partials ⚠️

📢 Thoughts on this report? Let us know!