* fix(ui): remove artificial maximum width limit on provider header plan label

Co-authored-by: Lucenx9 <185146821+Lucenx9@users.noreply.github.com>

* fix(ui): let header plan label yield beside the account on narrow popups

Without fillWidth, the uncapped plan label kept its full implicit width
while the account absorbed all shrinking, collapsing to zero width on
narrow popups. Filling lets both labels share the squeeze with elision
and hover tooltips, matching the account label pattern.

The ceiling on the cap absorbs the fill distribution's integer rounding:
with an exact implicitWidth cap, a fitting plan (e.g. 14.39px laid out at
14px) was misreported as truncated, growing a redundant tooltip.

Update the UI regression assertion to pin both layout properties and
correct the CHANGELOG wording (the plan elides right, not middle).

* fix(ui): add fillWidth and ceil implicitWidth to provider plan label

Co-authored-by: Lucenx9 <185146821+Lucenx9@users.noreply.github.com>

---------

Co-authored-by: google-labs-jules[bot] <161369871+google-labs-jules[bot]@users.noreply.github.com>
Co-authored-by: Lucenx9 <185146821+Lucenx9@users.noreply.github.com>