chore(deps): bump ratatui to 0.26.1

bumps msrv to 1.70

This necessitated 3 changes to the codebase:
- `Spans` was renamed to the more ergonomic `Line` type.
- `Frame` no longer requires a backend type parameter.
- `Table::new` requires a widths parameter, so we use
  `Table::default().rows(rows)` instead of `Table::new(rows)`.

.github/workflows/ci.yaml

@@ -51,8 +51,7 @@ jobs:
         os: [ubuntu-latest, macos-latest, windows-latest]
         rust: [stable]
         include:
-          # Make 1.64 MSRV, as it's Tonic 0.10's MSRV.
-          - rust: 1.64.0
+          - rust: 1.70.0
             os: ubuntu-latest
           # Try to build on the latest nightly. This job is allowed to fail, but
           # it's useful to help catch bugs in upcoming Rust versions.