API-created workflow runs are invisible in the UI (Default collection not indexed, no job meta written) #238

Environment: Ubuntu (kernel 7.0), RTX 5090 (Blackwell sm_120), NVIDIA driver w/ CUDA 13.3 userland, Modly AppImage v0.4.x, embedded Python 3.11.9, data dir relocated to a large secondary disk. Found while driving Modly headlessly (REST + MCP) for a game-asset pipeline.

Everything generated over the REST/MCP surface exists on disk but the app shows "No workspace assets are indexed yet" and empty Generate/Workflows views.

Three contributing causes:

1. POST /workflow-runs/from-image hardcodes the "Default" collection (the legacy /generate/from-image accepts a collection field; the canonical endpoint does not).
2. The Workspace Library indexer only scans the Workflows and Exports workspace roots (ALLOWED_ROOTS), so Default/ output is never indexed.
3. API runs never write the *.meta.json job records that the collections view reads.

Workaround we use: mirror outputs into workspace/Exports/<set>/ and click "Refresh assets".

Suggested fix: accept collection on /workflow-runs/from-image, include Default in the indexer roots, and/or write job meta records from _run_generation.