fix(webssh): add workspace spacing and fullscreen controls

[singchia]

Problem

The WebSSH terminal touches the content boundaries and fills the page without visual separation from its toolbar. Large screens make this especially noticeable.

Accepted solution

• Use responsive page gutters and a separate compact toolbar.
• Frame the terminal with a subtle border, rounded corners and internal spacing.
• Keep viewport-responsive height rather than imposing a fixed height cap.
• Add fullscreen/exit-fullscreen controls without recreating the SSH session.
• Exit fullscreen before opening the portal-based reconnect dialog; report fullscreen failures without closing SSH.

Validation

The trial frontend is deployed and the layout has been accepted by the maintainer. Real SSH checks passed for top, viewport resize, fullscreen entry/exit and reconnect. Dark/light screenshots were inspected and 12 focused tests passed.

Keep the issue open for public verification after marking it resolved.

[singchia]

Resolved in #456, squash-merged as ce5c620.

The WebSSH workspace now has responsive gutters, a separate toolbar, a subtly framed terminal, and native fullscreen controls. Terminal sizing remains viewport-responsive. Reconnect exits fullscreen before opening its dialog, and fullscreen errors do not tear down SSH.

Validation: all PR CI checks passed (Go build/vet/tests, frontend tests/build, deployment manifests and policy checks). All 12 focused terminal/page tests passed. Real SSH checks on the deployed trial covered top, resizing, fullscreen and reconnect; dark/light screenshots were inspected and the maintainer accepted the layout. The final commit additionally keeps exit-fullscreen available after disconnection.

Marked resolved; leaving this issue open for public verification.