Move bootstrap scripts from frontmatter to separate files

[Copilot]

• Understand current implementation (bootstrap in frontmatter)
• Design new approach (bootstrap in separate files named <markdown-file-without-md-suffix>-bootstrap)
• Update main.go to look for bootstrap files alongside markdown files
• Remove frontmatter bootstrap parsing logic
• Add tests for new bootstrap file loading
• Update documentation to reflect new bootstrap file structure
• Verify the changes work with manual testing
• Address code review feedback
• Fix build by skipping non-existent directories
• Use strings.TrimSuffix for clearer code

Original prompt

Rather than keep the bootstrap in a frontmatter, lets have it in a file. The file should be named '-bootstrap.

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[alexec]

@copilot fix the broken build.

[Copilot]

@copilot fix the broken build.

Fixed in dc188ea. The build was failing because the code tried to walk default memory directories that didn't exist. Added a check to skip non-existent directories before attempting to walk them.