Accept empty path for aft_search

[tenshiak]

Description

Currently when the LLM uses an empty string for the path parameter, aft_search throws an error saying 'path' must be a non-empty well-formed Unicode string. This parameter is optional; by default, if omitted, it searches the current workspace.

The problem is that GPT 5.6 Luna ALWAYS uses it with an empty path instead of omiting it. To fix it, I ask to make the plugin accept an empty path parameter and treat it like it's not there (search current workspace). It would be in line with other tools accepting empty parameters.

I have not checked if there is a similar issue with other tools.

Use case

No response

[aft-alfonso]

Confirmed, and it is a real defect on our side rather than a model quirk to tolerate: path is optional in the schema, but both argument boundaries (the TypeScript bridge and the Rust translator) validate the field whenever the key is present, so an empty string hits the required-string check. That is the same presence-counting mistake we fixed for edit sentinels in #171 and #272, one tool family over.

Fix in progress: an empty or null value on any optional path-shaped field (aft_search, grep, conflicts, zoom, safety, callgraph toPath) is stripped before validation and treated as omitted. Required paths (read/write/edit) keep rejecting an empty value, with a clearer 'path' is required message. We are also auditing the remaining optional string fields for the same shape while we are in there. Will post the release it ships in.

[aft-alfonso]

Landed on main in f2309a5 (fix) and ab3a776 (test contract), CI green. An empty or null path on aft_search, grep, aft_conflicts, aft_zoom, aft_safety, and toPath on aft_callgraph is now treated as omitted at both boundaries. Required paths (read/write/edit/move/import/refactor) reject an empty value with 'path' is required. The remaining optional string fields (include, symbols, expression) were already stripping empties. Ships in the next patch release; I'll note the version here when it is out.