refactor: remove dead code from autocomplete directory

[markijbema]

Summary

Removes unused code from the autocomplete directory to improve maintainability and reduce codebase complexity.

Changes

• Remove unused ranking functions (rankAndOrderSnippets, fillPromptWithSnippets) that were marked with //MINIMAL_REPO comments
• Delete test file for removed ranking functions
• Remove deprecated AutocompleteSnippetDeprecated type
• Refactor RootPathContextService to use AutocompleteCodeSnippet directly
• Clean up commented-out code in RootPathContextService

Testing

• All 43 tests in RootPathContextService pass
• Type checking passes
• Linting passes

Impact

• 4 files changed, 15 insertions(+), 307 deletions(-)
• No breaking changes - maintains full backward compatibility

[changeset-bot]

⚠️ No Changeset found

Latest commit: 1b424e1

Merging this PR will not cause a version bump for any packages. If these changes should not result in a new version, you're good to go. If these changes should result in a version bump, you need to add a changeset.

This PR includes no changesets

When changesets are added to this PR, you'll see the packages that this PR includes changesets for and the associated semver types

Click here to learn what changesets are, and how to add one.

Click here if you're a maintainer who wants to add a changeset to this PR