Merge pull request #1 from neongreen/copilot/fix-b8ac6de0-e860-464f-9b6c-fa9022a5ffad

Add markdown-format: A Go-based markdown formatter with one sentence per line

Author: neongreen

markdown-format/.gitignore

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+# Binaries
+markdown-format
+*.exe
+*.exe~
+*.dll
+*.so
+*.dylib
+
+# Test binary
+*.test
+
+# Output of go coverage tool
+*.out

markdown-format/README.md

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+# markdown-format
+
+A Go-based markdown formatter that reformats markdown files with one sentence per line.
+
+## Features
+
+- Uses [goldmark](https://github.com/yuin/goldmark), a well-maintained CommonMark-compliant markdown parser
+- Formats paragraphs with one sentence per line
+- Preserves markdown structure:
+  - Headers
+  - Lists (both ordered and unordered)
+  - Code blocks (fenced and indented)
+  - Blockquotes
+  - Inline formatting (bold, italic, links, images, inline code)
+  - Horizontal rules
+
+## Why one sentence per line?
+
+Formatting markdown with one sentence per line makes it easier to:
+- Track changes in version control (git diffs are clearer)
+- Review and edit individual sentences
+- Collaborate on documents
+
+## Installation
+
+```bash
+go build
+```
+
+## Usage
+
+Format a markdown file:
+
+```bash
+./markdown-format input.md > output.md
+```
+
+Read from stdin:
+
+```bash
+cat input.md | ./markdown-format - > output.md
+```
+
+## Example
+
+Input:
+```markdown
+# Hello
+
+This is a paragraph. It has multiple sentences. Let's format it!
+```
+
+Output:
+```markdown
+# Hello
+
+This is a paragraph.
+It has multiple sentences.
+Let's format it!
+```
+
+## License
+
+MIT License - See LICENSE file in the repository root.

markdown-format/go.mod

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+module github.com/neongreen/mono/markdown-format
+
+go 1.24.7
+
+require github.com/yuin/goldmark v1.7.13

markdown-format/go.sum

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+github.com/yuin/goldmark v1.7.13 h1:GPddIs617DnBLFFVJFgpo1aBfe/4xcvMc3SB5t/D0pA=
+github.com/yuin/goldmark v1.7.13/go.mod h1:ip/1k0VRfGynBgxOz0yCqHrbZXhcjxyuS66Brc7iBKg=