ignore closed issues and prune them from the state

[max-tet]

Currently, the state file gets polluted by all the closed issues. The fix has two parts:

1. make sure that closed issues are always ignored
2. add a prune step at the start of each tick that removes all issues from the state file that are closed

[ClaydeCode]

Preliminary Plan

Approach

get_assigned_issues() already fetches only state="open" issues, so closed issues are never actively processed. The real problem is that state.json accumulates entries for issues that were closed after being worked on — these entries just sit there forever.

The fix is a prune step at the start of each tick in main() (in orchestrator.py) that:

1. Iterates all entries in state.json
2. For each one, fetches the issue via the GitHub API and checks if it's closed
3. Removes closed entries from state

This also naturally satisfies part 1 of the issue — any entry that somehow refers to a closed issue gets pruned before the main processing loop runs, guaranteeing it won't be acted on.

I'll add a _prune_closed_issues(g, issues_state) helper in orchestrator.py and call it once per tick after loading state, logging each removed entry. Need to handle API errors gracefully (skip/warn rather than crash).

No clarifying questions — this is straightforward.

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This looks like a small issue. React with 👍 to approve this preliminary plan and proceed directly to implementation.

[ClaydeCode]

Implementation complete — PR opened: #68