feat(core-status): resizable columns, a remembered mode, and the core's build

[kirillDevPro]

What & why

Five gaps in the Core Status panel, plus the reason one of them only looked like a gap.

• By-IP columns are draggable. Clamped per column, and once the row stops fitting they shrink
  together by one shared factor — the view is a tree, so there is no horizontal scrollbar to fall
  back on and clipping the right-hand columns was the old behaviour. Widths persist per context;
  double-click frees one column, Shift+double-click frees all.
• The mode tab is remembered (By IP / Flat / Alerts), with the docked panel and a detached
  window keeping separate answers.
• The alerts gear popup opens under its own button, right-aligned, on one geometry scale.
• The core's MoonBot build gets a column in both modes, with an agreement rollup on a collapsed
  server row. It previously reached the UI only inside a ConnFault, so a healthy core showed
  nothing — it now travels as its own retained message, dropped on any non-Ready status. Rendered
  dotted (769 → 7.69) through a new moon_core::util::fmt::core_build, shared with the fault
  hover so the two surfaces cannot disagree.
• The flat view groups by exchange, with the same logos the left rail uses. MoonDataTable has
  no section-row concept, so each heading is a synthetic row whose caption rides MoonUI's new row
  banner (feat(data-table): lay one element across a whole row MoonUI#53). Sorting reorders inside a section and never moves one.
• The IP column was never empty. The mask defaulted to on and printed twelve asterisks. The
  address now shows, the header carries the single control that hides it, and losing panel focus
  no longer re-masks.

How to verify

cargo test --workspace     # 2788 passed, 0 failed, on this branch alone

core_build_zero_pads_single_digit_minor_versions is mutation-proven: changing {:02} to {}
turns 707 into 7.7, which reads as older than a neighbouring 7.09. That is the boundary the
test asserts, not the easy 769 case, which stays green under the mutation.

Verified by hand against 56 live cores: drag, clamp, shrink and reset; the row never spills past
the panel edge even with four columns dragged to their maximum; the remembered tab survives a full
restart; a real build disagreement (7.70 beside 7.69) shows up in the wild.

Note

Needs Moonbot-Tech/MoonUI#53 (merged) — the Cargo.lock bump to that revision is in this PR.