Let the training dialogs email progress reports through viame monitor

[mattdawkins]

Adds an optional Email progress reports to field to the desktop and web training dialogs. The address is passed to viame train as --monitor-email, which starts VIAME's training monitor next to the run (VIAME/VIAME main 879c9a753 and later). The monitor emails a start message, validation statistics every few epochs, error/deadlock notices and a final finished/failed report, and keeps train.log plus a status trail in the run's output directory.

Mail delivery is configured on the training machine rather than in DIVE: VIAME_SMTP_SERVER (and VIAME_SMTP_USER / VIAME_SMTP_PASSWORD) in the environment of DIVE Desktop or of the training worker, or a local sendmail on Linux. Without either the reports still go to the status trail. Documented in the training section of the pipeline docs.

Changes:

• Api.runTraining takes a trailing optional monitorEmail; the desktop job args and the server's RunTrainingArgs / TrainingJob carry it through.
• Desktop launcher and the training worker append --monitor-email when set.
• Shared isValidEmail helper validates the field in both dialogs; the train button stays disabled while the address is malformed.

Verified with typecheck, lint and the client unit tests; the desktop path was exercised end to end against a local VIAME build with a debugging SMTP server.

🤖 Generated with Claude Code

https://claude.ai/code/session_01W1C4QY6hxjHaUPJfWPfQuu

[BryonLewis]

For this I would rather have some standardized way that VIAME reports back progress (either throught a file, function or standarized stdout) that could then be used by desktop and web to report back progress. For Web we would then use the girder way for sending the email and for desktop we could present popup dialogs or other options.