push: 5 explicit update actions, drop auto-detect prompt language

[moshe-kabala]

Summary

Mirrors engine PR #2326 (and node-server PR for update-actions-explicit). The CLI now asks the user to pick exactly what changed instead of leaning on engine auto-detect:

• 5 explicit options in AskForEvaluatePlan (no more "(auto-detected: …)" hint, no more "Auto-detect …" tail in PrintEvaluatePlan).
• survey.Required validator — empty submit isn't valid anymore; a push without an eval intent should drop --eval.
• -u / --update gains metric_direction / metric-direction / direction aliases, mapping to the new UPDATEACTION_UPDATE_METRIC_DIRECTION enum value.
• metadata and metric still trigger a full re-evaluation (server-side resetEvaluate delegation).

Prompt before → after

Before:

? What did you change in your code? (auto-detected: added meta/viz, metric-direction, insight-config)
  [ ] Edited an existing metadata
  [ ] Edited an existing visualization
  [ ] Added or edited a metric
  [ ] Force re-run insights

After:

? What did you change in your code?
  [ ] Added or edited a metadata             — triggers full re-evaluation
  [ ] Added or edited a metric               — triggers full re-evaluation
  [ ] Edited metric direction or insight-config — cheap update
  [ ] Added or edited a visualization        — regenerate all visualizations
  [ ] Reinforce insights                     — regenerate insights from scratch

Files

• pkg/tensorleapapi/model_update_action.go — add UPDATEACTION_UPDATE_METRIC_DIRECTION
• pkg/model/evaluate.go — 5-option ChangeKey enum + table-driven planUpdateEvaluate, survey.Required validator, dropped auto-detect language, updated FormatEvaluatePlan / PrintEvaluatePlan
• cmd/root_cmd/push.go — --update help lists all five values + notes metadata/metric trigger full re-eval; Long help removes "(auto-detects changes)" phrasing
• docs/push-examples.md — matches new prompt + plan output, adds metric_direction row

Test plan

• leap push -o <name> -e → prompt shows 5 options, empty submit rejected
• leap push -o <name> -u metric_direction → "Update metric direction" plan, no full re-eval
• leap push -o <name> -u visualization -u insights → both bullets shown
• leap push -o <name> -u metric → "Re-evaluate (full)" plan, dispatches resetEvaluate
• leap push -o <name> -u metedata → typo errors with allowed-values hint
• Legacy -u update_visualization long-form still parses

Rollout

Depends on engine PR #2326 landing + @tensorleap/engine-contract@0.0.408 published (so the node-server route is live and accepts the new action value).

🤖 Generated with Claude Code

[asafyehezkel]

LGTM