[UI] Add /experiments listing page with filterable experiment cards

[UI] Add /experiments listing page with filterable experiment cards

ID: f605325e-dd9 Priority: 88 Type: one_shot Status: open

Goal

Create a browsable /experiments page showing all 188 experiments with filtering by type, target gene, and disease. Cards should show title, score, cost, and linked hypothesis count.

Acceptance Criteria

Work Log

2026-04-20 20:16 PDT — Slot 44

• Started from a stale worktree assignment and selected the open one-shot task f605325e-dd9.
• Reviewed the existing /experiments implementation and found the listing page and JSON endpoint already present, with type and disease filters but no target-gene filter.
• Plan: add target-gene filtering to /experiments and /api/experiments, keep the query read-only, then verify the page and API route return filtered data.

2026-04-20 20:18 PDT — Slot 44

• Implemented target-gene filtering for /api/experiments and /experiments, including preserving the selected target across type/sort/pagination controls.
• Switched the /experiments listing query to get_db_ro() because the route is read-only.
• Tested: python3 -m py_compile api.py; FastAPI TestClient GET /api/experiments?limit=5&target_gene=AQP4, /experiments?target_gene=AQP4, and /experiments?target_gene=AQP4&ajax=1 all returned 200.
• Result: Done — /experiments now supports filtering by type, target gene, and disease.