feat(webkit): add a border prop to LogView

[gabriel-lisboa-azion]

Summary

The log shell always drew its own outline and corner radius. Placed inside a surface that already frames it — an accordion panel, a drawer, a card — that produced a visible box inside a box, and the only escape was for the consumer to override the border with a class.

border defaults to true, so nothing changes for existing consumers. Setting it false drops the outline and the radius together (both hang off data-border, so one attribute governs the pair) and leaves the internal header/footer dividers alone — those separate regions within the shell, not the shell from its host.

Tests

Full webkit suite green (83 files / 1694 passing, 6 skipped), eslint + vue-tsc clean, catalog:check regenerated (the new prop is in the MCP catalog). New coverage:

• data-border is "true" by default and absent when border: false — the attribute is the whole mechanism, so its presence is the thing worth asserting rather than the classes hanging off it;
• the Flush story fixture composes and renders the borderless shell.

Visual regression

Baselines are regenerated and committed (ubuntu-latest, via the app-storybook-generate-baseline dispatch). Delta: 6 files, all new, nothing moved, no orphans.

• 6 new — components-code-logview--flush* across the 6-mode matrix.
• 12 unchanged — Default and Loading came back byte-identical, which is the proof the prop is additive: the border stays on by default and no current consumer's rendering shifts.

I checked the Flush baseline itself rather than trusting the count: the card draws one frame, the shell inside draws no second outline or radius, and the internal header/body divider is retained. That is exactly the documented split between framing the shell and separating regions within it.

Notes

• Additive prop, default preserves current rendering — no migration for consumers.
• Spec, argTypes, story and "Show code" snippet all updated together, so the docs panel stays paste-and-run.
• No new dependency. No breaking change.