Post-cut release updates for 26.05 (#3609)

## Summary
- run the post-cut release helper in `post-cut` mode with
`--version-after-this 26.05`
- bump top-level `VERSION` from `26.03.00` to `26.05.00`
- rotate docs switcher to make `26.05` preferred while keeping `26.03`
- add `docs/legate/source/changes/2605.rst` and repoint
`docs/legate/source/changes/dev.rst`

Cut release branch

Post-cut release updates for 26.03 (#3525)

## Summary
- run the post-cut release helper in `post-cut` mode with
`--version-after-this 26.03`
- bump top-level `VERSION` from `26.01.00` to `26.03.00`
- rotate docs switcher to make `26.03` preferred while keeping `26.01`
- add `docs/legate/source/changes/2603.rst` and repoint
`docs/legate/source/changes/dev.rst`

Trigger CI for 26.01.00 (#3487)

Prepare 26.01.00 rc6 (#3483)

Undo NCCL restriction and update Legion pin (#3452)

* Undo NCCL restriction and update Legion pin

* cmake: propagate Legion max settings to CPM

Constrain NCCL <2.28 on branch-26.01 (#3445)

Mark v26.01.00.rc3 (#3405)

Mark v26.01.00.rc2 (#3398)

Bump legion for bugfix in legion profiler (#3313) (#3314)

(cherry picked from commit 40a4e58)

Co-authored-by: tisaac <[email protected]>