agami-save-correction

Saves a user correction so future queries learn from it. Always appends a (question, corrected_sql) pair to the subject area's example library under <artifacts_dir>/<profile>/prompt_examples/<area>/. Additionally, classifies the correction and — when applicable — applies a surgical edit to the semantic model itself (relationship fix, column metadata, or new metric) via the curation engine. Every model edit is validated before write; the validator is the binding gate, and a failed validation reverts. Shows the user a model diff for approval before any model mutation.