feat(flow): support D2 markdown blocks

[xxchan]

Summary

• add D2 |md block normalization for flow labels
• allow quoted D2 labels to span multiple lines
• convert release skill flow to D2 with readable markdown blocks

Testing

• uv run pytest tests/test_agent_flow.py -k d2

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[Copilot]

Pull request overview

This PR adds support for D2 markdown blocks (|md ... |) in flow definitions, allowing more readable multi-line labels in flowcharts. The implementation preprocesses markdown blocks into multi-line quoted strings before parsing, and the parser is updated to preserve newlines within quotes.

Changes:

• Added markdown block normalization in D2 parser with proper escaping and dedenting
• Extended parser to preserve newlines inside quoted strings for multi-line labels
• Converted release skill flow from Mermaid with Chinese labels to D2 with English markdown blocks

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 1 comment.

File	Description
tests/test_agent_flow.py	Added comprehensive test cases for markdown block parsing, escaping, dedenting, and error handling
src/kimi_cli/skill/flow/d2.py	Implemented markdown block normalization, helper functions for comment stripping, dedenting, and escaping, plus parser updates for multi-line quoted strings
.agents/skills/release/SKILL.md	Converted flowchart from Mermaid format with Chinese labels to D2 format with English markdown blocks

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[chatgpt-codex-connector]

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[devin-ai-integration]

✅ Devin Review: No Issues Found

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