Improve saved connection organization

[bifrost0x]

Summary

• persist an explicit order for saved connections inside each group
• add handle-based drag and drop with precise insertion positions across groups
• keep management and empty-pane launchers in the same persisted order
• require an in-app confirmation before moving the last connection out of a named group
• disable reordering while search filtering is active and explain why
• modernize the connection management UI and move advanced quick-connect options into a collapsible section

Implementation

• add an atomic server-side move_profile operation with source-group concurrency checks
• preserve legacy profile order until a group is normalized by its first move
• keep favorites derived and excluded from drag sources and targets
• return authoritative profile state after every move attempt
• update all six supported translations and frontend asset cache versions

Validation

• pytest tests -q - 1499 passed, 33 skipped
• npm run test:js - 164 passed
• npm run lint:js
• npm run vendor:check
• npx playwright test --forbid-only - 46 passed
• git diff --check

Implements the connection management direction from Discussion #93.