refactor(reporter): split JobsComponent rendering, fix build summary placement

[jaudiger]

This PR has two commits on the console reporter.

The first commit splits JobsComponent::draw_unchecked into smaller pieces. The draw function used to do everything inline; it now delegates to compute_visible_jobs, an OutputsComponent, and a render_summary method. The visible behavior is unchanged.

The second commit fixes the placement of the Build finished and Result lines from brioche build and brioche install. They used to be emitted through the reporter, so they landed above the TUI canvas, in the middle of the terminal output. They are now printed with eprintln! after shutdown_console, so they land below the canvas, like brioche run and brioche live-update already do.

Before (brioche build on aws_c_auth):

Build finished, completed 1 job in 11.18s
Result: 68766d877e9a1dcaa7cb0f68dd4dab32de806b21902439fa3fd3855cde0dc12c
 1.72s ✓     Cache 100% 3.7 MiB / 3.7 MiB                                                                                                                                                                                  (std/core/recipes/process.bri:252:14)

After (brioche build on aws_c_common):

 1.54s ✓     Cache 100% 716.4 KiB / 716.4 KiB                                                                                                                                                                              (std/core/recipes/process.bri:252:14)
Build finished, completed 1 job in 6.89s
Result: aabd6937584bd6fd133d56416710b8314c7aee5d8e79b4808662dd8d56ffacb6