fix(cli): normalize whitespace-only search filters

[atharva-patill]

Summary

While looking at the search filters, I noticed that whitespace-only values passed to --file and --workspace were being ignored by the search pipeline, but they still appeared in the JSON filters output.

This normalizes both fields when building SearchFilters, so the JSON output reflects the filters that are actually applied.

Reproduction

./target/debug/ctx search foo --file " " --json | jq '.filters'

Before:

{
  "file": " ",
  "include_subagents": false
}

After:

Whitespace-only values are normalized away, so the file filter is no longer included in the JSON output. The same behavior now applies to --workspace.

Testing

• Added a regression test covering both --file and --workspace.
• Verified the updated JSON output manually.

[luca-ctx]

Added fmt, thanks for this!

[atharva-patill]

Added fmt, thanks for this!

Thanks! I missed the cargo fmt. I’ll make sure to run it first next time.