Port wiki markup detection and conversion from jira-ticket-cli PR #63.

Files to create:

• tools/jtk/api/wiki.go - Wiki markup detection and conversion
• tools/jtk/api/wiki_test.go - Unit tests

Features:

• IsWikiMarkup() - detects common wiki patterns
• WikiToMarkdown() - converts wiki markup to markdown
• Pipeline: wiki → markdown → ADF

Supported patterns:

• Headings: h1. through h6.
• Code blocks: {code}...{code}
• Monospace: {{text}}
• Links: [text|url]
• Images: !image.png!
• Blockquotes: bq. and {quote}...{quote}
• Bullet lists: * item, ** nested
• Noformat: {noformat}...{noformat}
• Horizontal rules: ----

Source: open-cli-collective/jira-ticket-cli#63