fix(web): keep the ring border on focused overlays

[imneov]

What type of PR is this?

• bug fix
• feature
• cleanup / refactor (no behaviour change)
• documentation
• install / chart
• CI / tooling
• breaking: API, config key, chart value, or CRD field changed

What this PR does and why

The site-wide no-focus-ring rule in web/packages/ui/styles/base.css zeroes --tw-ring-shadow on any focused element. [data-slot='card'] was excluded because a card's ring-1 is its border, not a focus ring. Overlay shells are the same case and were missed: menus, popovers, selects, comboboxes and dialogs have no border — bg-popover + ring-1 ring-foreground/10 is their edge — and Base UI moves focus to the shell when it opens (dropdown-menu-content carries tabindex="-1"). So the edge was wiped exactly while the panel was on screen: a white panel on the white page kept only a faint shadow, and the top-bar avatar menu read as a line of text floating under the header.

The exclusion now covers container surfaces by their naming convention (data-slot ending in -content) next to card, so a new overlay cannot regress the same way. Nothing else changes: form controls still get their focus ring suppressed (that is the deliberate decision this rule exists for), and card behaves as before.

Which issue(s) this PR fixes

Fixes #58

How it was tested

• web/: npm run typecheck, npm test (272 passed, 31 files), vite build — all on this branch.
• Loaded the built bundle in the live preview and measured the open menu:
  • before: --tw-ring-shadow: 0 0 #0000 while document.activeElement is the popup;
  • after: --tw-ring-shadow: 0 0 0 1px <--tw-ring-color> and box-shadow contains oklab(0.145 0 0 / 0.1) 0 0 0 1px, with the popup rect unchanged (128×32 at the same position).
• Regression probes on the same page: a focused <input class="ring-2 ring-ring"> still computes --tw-ring-shadow: 0 0 #0000, and a [data-slot='card'] with ring-2 still computes 0 0 0 2px — both unchanged.
• Screenshots (top-right, before / after) reviewed during the session; before shows only the label with no edge, after shows the 1px panel border.

Checks

• go test ./... and gofmt -l . is empty
• npm run typecheck && npm test && npm run build in web/ (if web/ changed)
• helm lint --strict helm/console (if the chart changed)
• Docs updated where behaviour, a config key or a chart value moved
• No internal hostnames, IPs, registries or credentials

Notes for reviewers

One file of CSS plus a CHANGELOG line. The *-content suffix is the design-system convention for an overlay shell (dropdown-menu-content, popover-content, select-content, combobox-content, dialog-content, alert-dialog-content, dropdown-menu-sub-content); tabs-content / tooltip-content / empty-content come along for the ride, which is harmless — no form control ends in -content.

The focus-visible:ring-2 on ResourceTable rows stays suppressed by this rule as it is today; if rows should show a focus ring again, that is a separate decision (the rule is the site-wide "no focus ring" call, WCAG 2.4.7 traded deliberately).

Release note

Overlay menus, popovers, selects, comboboxes and dialogs keep their 1px border while open; it was being erased by the site-wide no-focus-ring rule, which left a white panel on a white page looking like floating text.