feat: allow omitting declaration locations

[kuishou68]

Implements the output-size request in #44.

Adds --no-locations to omit the trailing Declaration locations section while preserving the summary, file list, and source blocks. The default output is unchanged. Includes parser and renderer tests plus CLI documentation.

Validation:

• git diff --check passed.
• Focused Bun tests could not run because Bun is not installed in this environment.

[dzhng]

Thanks for working on the declaration-location output. This older implementation is superseded by the newer PR #58, which covers the same request with a more complete flag and test surface, so I’m closing this duplicate.