Build the failure context through the title's template builder with an empty MediaInfo, and blank season_episode, absolute and date in season mode. Document {part} and add a docs-to-code parity test.
New post_scripts config and repeatable --postscript flag run a command per output, season/album folder, or run, substituting filename-template variables into pre-tokenized argv. The REST API rejects hook commands.
Closes#150