Feat/expose advanced workflow management apis

[javier-aliaga]

Description

Closes the documentation and example gap for the advanced workflow management APIs. No SDK code was needed.

ListInstanceIDs, GetInstanceHistory and RerunWorkflowFromEvent are already reachable from the Go SDK: client.NewWorkflowClient() returns *durabletask-go/workflow.Client directly, so the SDK inherits the full upstream surface. What was missing was any documentation or example for them. None of the three appeared in the Go client guide or in examples/, and neither did 7 other management operations already available on the same client.

This PR adds:

A new examples/workflow-management example. It chains the three APIs the way a caller is expected to use them: list the instances, read one instance's history to locate a rerunnable event, then rerun from that event with a replacement input. Registered in the validate_examples.yaml matrix so CI exercises it.

A "Managing workflows" section in the Go client guide. Covers the three APIs plus the behaviour that is not evident from the signatures:

• the pagination loop ends when the continuation token comes back nil, and the page size is an upper bound rather than an exact count;
• GetInstanceHistory reports NotFound once state is purged;
• rerun requires a terminal, non-child source instance, targets an event's own EventId rather than its position in the history, and accepts only TaskScheduled, TimerCreated and ChildWorkflowInstanceCreated events;
• which work is replayed and which is re-executed. Work that completed and was recorded before the target event is replayed from history, but earlier work that had not completed (in-flight activities, unfired timers, unfinished child workflows) is re-executed in the new instance. In a parallel workflow this also covers an activity whose completion was recorded after the target event. This matters for activities that are not idempotent.

Listing requires a state store with actor support that can list keys; the Redis component in the example's config/ qualifies.

Issue reference

Please reference the issue this PR will close: #833

The API list being audited comes from dapr/dapr#9729.

Checklist

Please make sure you've completed the relevant tasks for this PR, out of the following list:

• Code compiles correctly
• Created/updated tests
• Extended the documentation

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 56.71%. Comparing base (c9af9fd) to head (9b398a8).
⚠️ Report is 3 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #837      +/-   ##
==========================================
- Coverage   56.73%   56.71%   -0.03%     
==========================================
  Files          52       52              
  Lines        3784     3784              
==========================================
- Hits         2147     2146       -1     
- Misses       1482     1483       +1     
  Partials      155      155              

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