Three issues caused the Logs view to appear blank during a real pipeline run:
1. `from run import step_fetch, step_link` was outside the worker's
try/except/finally. An import failure silently killed the thread,
leaving _pipeline_done uncalled and the Run button stuck disabled
forever. Now wrapped in its own try/except that posts the error to
the log and resets the UI.
2. `build_server_index` makes N sequential HTTP requests (one per mod
folder's meta.cpp) with no output during the scan. Added an optional
`progress_fn(current, total, name)` callback; step_fetch wires it to
print progress every 25 folders so the log never goes silent.
3. No immediate feedback after clicking Start — the log was blank until
the worker thread started printing. Now posts a "Pipeline started"
banner from the main thread before the worker launches.
Pipeline: parse HTML presets, compare modlists, download from Caddy
file server, create junctions/symlinks to Arma 3 Server directory.
Includes update/sync flows, missing-mod reporting, OS compat layer,
shared config, dep checker, comprehensive test suite (71 tests).
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
