Reconcile the staged-projection and Diagnostics feature work with the CI
quality-gate changes from origin/main. The origin side of every conflict was
lint-only, so the feature imports were kept and the ruff fixes re-applied:
- keep the branch's added imports (timefmt, activity_readout, projection
ladder helpers) and drop the unused ones ruff reported
- restore `noqa: E402` on the post-bootstrap imports in fenris-monitor and
keep the `noqa: F401` re-exports in the TUI that tests assert on
- make the TUI monitoring-glyph test clock-relative instead of pinned to a
fixed date
Use lifetime written bytes from the current segment's newest published
sample in the headline formula, select the Percentage-Used-implied
baseline after two increments in the segment (otherwise show the
too-coarse fact), and judge horizon agreement across existing horizons.
Make the vacuous projection tests assert unconditionally and add
coverage for implied-baseline gating and single-horizon agreement.
xavierk