When the client's retries can't clear a partial-instance failure, the
TUI holds the last good frame and lets the staleness dot and captured
age surface it, instead of replacing good data with the unreachable
banner. First load (no prior frame) still shows the partial. Shared
HasUnreachableInstance moves onto ConnectionList.

Selecting a row in the detail view's blocker tree prepended a caret and
shifted the row text, a layout jump the table view doesn't have. Pad
unselected rows by the caret width so the text stays put on selection.

The default (Postgres) view rendered via lgtable, which distributes the
terminal width across columns and spreads them with large gaps when the
content (notably the trailing QUERY column) is short. Route it through the
same content-based width + manual padding layout the Vitess/processlist
view already used (generalized to tightColumnWidths / renderTightRow), so
columns stay packed at the left regardless of terminal width.

Remove the always-true i>=0 guard in the tight table renderer (carried
over from the old lgtable header-sentinel path) and the redundant
consecutiveErrors==0 assertion in the first-load partial test (the view
assertions already cover that branch).