fix: search roles server-side in the space permissions picker

[NagariaHussain]

Problem

Only the first 20 enabled roles were selectable under Space Settings → Permissions. The role list passed pageLength: 0 intending "no limit", but frappe-ui falls back to 20 for a falsy pageLength, and the picker then filtered that single page in the browser — so every role past the first page was unreachable.

Closes #709

Solution

• Replaced the hand-rolled dropdown with frappe-ui's Combobox. It is reka-ui based, so its portalled popover works inside the settings dialog — which is why the old dropdown was hand-rolled. Keyboard navigation and ARIA combobox semantics come along for free.
• The typed query now drives a debounced server-side like search on Role instead of a client-side filter over one page.
• Pick a role to fill the field, then Add it to the table, same as before.
• Also: the old loading branch read allRoles.loading, which the list resource never exposes, so the spinner never rendered.

Tests

New e2e/tests/space-permissions-role-search.spec.ts seeds a role named to sort last alphabetically, searches for it, adds it and asserts it persisted. Verified it fails against the pre-fix code and passes after.

🤖 Generated with Claude Code

[greptile-apps]

Confidence Score: 5/5

The PR appears safe to merge.

No concrete changed-code failure was established from the available repository evidence.

_{Reviews (1): Last reviewed commit: "style(permissions): make the Beta badge ..." | Re-trigger Greptile}