v0.26.0
This release brings support for Opus 4.8 as well as a few minor improvements.
On the visual side, long plans are now more reviewable with a sticky table of contents that appears in the gutter:

- Cleaned up the Custom Agents system, removed unnecessary configuration options
- Fixed SSH runtime worktree bug
- Bounded syntax highlighting runtime to avoid long stalls
- Many bug-fixes and tweaks to the Goal system