Preserve TUI picker selection after detail views

[aidandaly24]

Problem

PaginatedTablePicker keeps its cursor only in component-local state. Opening a selected resource unmounts the picker, so returning from its detail screen resets the cursor to the first row. This affects every resource flow built on the shared picker.

Expected experience

• preserve the selected row by stable value when a picker opens a detail screen
• restore that row when the user returns with Escape
• apply the behavior once in PaginatedTablePicker for every resource family
• keep existing pagination, resize, transition, and filtering reset behavior
• avoid resource-specific cursor state in individual screens

Verification

• shared Harness picker regression
• Memory Event picker regression
• full repository coverage suite
• TUI-harness validation across both resource families