Fix cramped Agentlet connection-token Settings layout

[mydmdm]

Problem

The Agentlet connection-token setting becomes severely cramped at narrower Settings widths. Its description and the token controls currently share one horizontal row, so the input and action buttons consume the available width and collapse the explanatory text into a very narrow, word-wrapped column.

This makes the setting difficult to read and creates avoidable visual imbalance even though the underlying connection-token behavior works correctly.

Requested outcome

Use a responsive two-row layout for this setting:

• Keep the title, information affordance, and explanatory text together in a full-width upper row.
• Place the replacement-token input, Save changes, and Copy connection command controls in a lower row.
• At widths where the lower row fits, let the input grow while the buttons retain usable content-sized widths.
• At narrower widths, wrap or stack the controls without clipping labels, overlapping content, or compressing the description.
• Preserve existing token visibility, validation, saving, copy-command behavior, accessibility, and localization.

Investigation requirements

Verify the current Settings row/layout primitives and the exact breakpoint behavior before implementation. Reuse or extend the canonical Settings/Common UI layout rather than adding a one-off absolute width workaround. Check nearby settings for regressions and determine whether the reusable primitive or only this token setting owns the defect.

Acceptance criteria

• The connection-token description remains comfortably readable and is not narrowed by the input or buttons.
• The controls appear below the description and adapt cleanly across supported Settings widths.
• Input and button labels are neither clipped nor forced outside the setting container.
• Existing save and copy-command behavior is unchanged.
• Keyboard navigation, focus states, accessible labels, and localized text remain correct.
• Focused responsive-layout regression coverage is added where practical.
• Relevant UI documentation is updated if a shared Settings layout contract changes.

Non-goals

• Changing connection-token generation, storage, permissions, or API behavior.
• Redesigning unrelated Settings sections.
• Reopening Allow configuring the Agentlet connection token with generated fallback #254; this is a focused presentation defect discovered after that functionality shipped.

Context

Follow-up to the connection-token delivery tracked by #254 and #265.