`tip` was none|chamfer, chamfer cutting every free end. It is now none|start|both: `start`
chamfers the end the thread starts from, refused when that end is not free (a shoulder, or a
stop inside the face), and `both` every free end as `chamfer` did. The dialog's Tip pick offers
None, Start and Both; `tip: chamfer` in a command names its replacements.
The thread's end options (runouts, tip, chamfer angle and depth) came without a format
change file; `pending/thread-ends.rs` records them and rewrites a saved `tip: chamfer` to
`both`.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
jyvikoandClaude Opus 5.5
2c4212c042