Run workflows through managed hook sessions

[Xmaster6y]

Summary

• add Workflow.session(model) and WorkflowSession.run(data) so imperative capture, replacement, and stopping can wrap a complete workflow run
• associate the executed WorkflowPlan with the session HookProgram in WorkflowResult
• retain ordered repeated capture values while preserving the existing latest-value API
• keep Getting Started focused on Workflow composition and move HookSession concepts into a dedicated executable tutorial notebook

Validation

• just checks
• just tests (614 passed, 1 skipped)
• just docs (passed with the existing AutoAPI cyclic-import warning)
• offline HookSession and declared-workflow notebooks executed from fresh kernels

Closes #114

[chatgpt-codex-connector]

Codex Review Summary

This comment shows the latest Codex review activity on this pull request.

Review	Status	Commit	Review trigger
📝 Code Review	✅ Completed 2026-08-31T09:41:00.504549Z	9279b96	PR opened

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 98.30%. Comparing base (c18ce26) to head (9b0e43b).

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #123   +/-   ##
=======================================
  Coverage   98.29%   98.30%           
=======================================
  Files          52       52           
  Lines        3929     3947   +18     
=======================================
+ Hits         3862     3880   +18     
  Misses         67       67           

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[cubic-dev-ai]

No issues found across 5 files

Confidence score: 5/5

• Automated review surfaced no issues in the provided summaries.
• No files require special attention.

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<sub>Auto-approved: Adds Workflow.session and WorkflowSession.run to wrap workflow runs in a managed HookSession, preserves repeated capture values with a new values list, and adds program to WorkflowResult; includes tests and docs.

Re-trigger cubic</sub>