[Editorial] Move spec files to root directory and remove unused files

[monica-ch]

This PR reorganizes the repository structure by moving specification files to the root directory per #1009 and cleaning up unused files/folders. This change simplifies the repository structure and makes it more maintainable.

Changes made:

1. Moved key specification files to root:

   • Moved docs/index.bs → index.bs
   • Moved docs/sw-registration-figure.svg → sw-registration-figure.svg

2. Updated configuration files to reflect new paths:

   • .github/workflows/generate.yml: Updated SOURCE and DESTINATION paths
   • .pr-preview.json: Updated src_file path
   • Updated references in documentation

3. Removed unused files from

• Publish folder
• docs/spec/
• docs/v1/

Testing:

• Verified Bikeshed processing works with new file locations
• Confirmed GitHub Actions workflow builds correctly
• Checked all SVG references remain intact

[monica-ch]

@yoshisatoyanagisawa Can you please take a look at SW spec repo directory changes, thanks!

[yoshisatoyanagisawa]

For the updated files, it seems like the line break characters have been changed from LF to CRLF. Is this intentional?

[monica-ch]

Reverted to LF, Thans for checking!

[yoshisatoyanagisawa]

LGTM
Thank you for working on this.