fix: optimize workspace display cursor

[sheepbox8646]

Summary

• hide the remote Xvnc cursor at the source with -nocursor and restart stale Xvnc processes that lack the flag
• add a display cursor metadata data channel that maps remote cursor geometry to native browser/system cursor types
• avoid hiding or replacing the user system cursor with remote cursor images
• nudge the last pointer position after keyboard input to keep terminal text updates flowing without requiring mouse movement

Validation

• go test ./internal/display ./cmd/bridge ./internal/handlers
• pnpm exec eslint apps/web/src/pages/home/components/display-pane.vue
• git diff --check && git diff --cached --check
• pre-commit hook: full Go test and Go lint passed during commit