Add search parameter to project list endpoint

[JohnRDOrazio]

Context

The project list endpoint (GET /api/v1/projects) has no search capability. The frontend was doing client-side filtering, which only searches loaded pages and misses results in unpaginated data.

Implementation

Add an optional search query parameter that performs case-insensitive ILIKE search on project name and description.

Related

• fix: project list shows misleading count without pagination ontokit-web#52 — frontend pagination and search improvements
• PR #28 — implementation

[JohnRDOrazio]

Resolved by #28.