Grid row-click gating blocks keyboard and touch users from opening details

Background

While addressing Copilot review feedback on #584, four related comments surfaced a consistent keyboard-accessibility regression in the monitor grids. The PR intentionally gates onRowClick on _pointerActive (set only via @mousedown) so that programmatic row activation doesn't open the details panel — a good fix for the original bug, but it means keyboard and touch/pointer users now have no way to open details on those grids.

Four affected call sites, same root pattern:

These need to be fixed together, not one commit per component, so they were deferred from #584 rather than partially applied.

Proposed approach

Apply the same fix to both grids:

1. Broaden pointer gating — replace @mousedown with @pointerdown (covers mouse, touch, pen) and/or @click, so touch users on tablets/phones can also open details.
2. Add keyboard activation — handle Enter and Space on the currently active row. The grid's active-item-changed still fires on keyboard navigation; instead of discarding those events when _pointerActive is false, treat a keyboard commit (keydown with Enter/Space) as an explicit "open details" signal equivalent to a click.
3. Consider an accessible secondary affordance — an explicit details button or overflow menu item per row would remove the ambiguity entirely. Worth weighing against the UX goal of "click row = open" that drove the original change.

Acceptance criteria

• Mouse click on a row opens details (regression check — current behaviour).
• Tap on a row (touch device) opens details.
• Keyboard user navigating rows with arrow keys and pressing Enter/Space opens details.
• Programmatic active-item-changed events (e.g. from code that sets grid.activeItem) do not open details — preserves the bug #584 originally fixed.

Context

• PR #584 inline threads (closed with reference to this issue):
  • https://github.com/sefe/dorc/pull/584#discussion_r3101698395 (env-monitor.ts:189)
  • https://github.com/sefe/dorc/pull/584#discussion_r3101698424 (env-monitor.ts:654)
  • https://github.com/sefe/dorc/pull/584#discussion_r3101698458 (page-monitor-requests.ts:186)
  • https://github.com/sefe/dorc/pull/584#discussion_r3101698477 (page-monitor-requests.ts:707)

Start with the row handling at the cited lines in src/dorc-web/src/components/environment-tabs/env-monitor.ts and src/dorc-web/src/pages/page-monitor-requests.ts, then review the linked PR #584 discussions. Trace how pointer, keyboard, and programmatic active-item-changed events reach onRowClick. Done means mouse, touch, Enter, and Space open details while programmatic activation does not, in both grids.