Fix workspace search debounce

[HussainAther]

Summary

Fixes workspace search filtering so requests are delayed until the user pauses typing rather than attempting to create an unused debounced callback.

Changes

• Creates a persistent debounced search-filter handler
• Cancels pending debounce calls when the component unmounts
• Uses a functional state update to avoid stale filter values

Testing

• Confirmed that typing rapidly in the workspace search field does not trigger a request for every keystroke
• Confirmed that the workspace list updates after the 500 ms debounce period
• Confirmed that tag and type filter values are preserved when updating the text filter