hub.toml.example documents fields that the config parser rejects

[ooloth]

Current state

hub.toml.example includes two commented-out fields — assigned_only = true and exclude_labels = ["wontfix", "duplicate"] — under the github-issues workflow config block (lines 48–50). Neither field exists in the actual WorkflowConfig::GithubIssues {} enum variant. A user who copies the example and uncomments these fields will get a TOML parse or deserialization error with no clear indication that the example is the source of the problem.

Ideal state

• Every field shown in hub.toml.example corresponds to an actual config field the parser accepts.
• A user can copy any commented block from hub.toml.example, uncomment it, and have the config load without error.
• If assigned_only and exclude_labels are planned future features, the example file annotates them as not yet implemented rather than showing them as valid config.

Out of scope

• Implementing assigned_only or exclude_labels as actual config fields.

Starting points

• hub.toml.example lines 48–50: the two fields that don't exist in the parser
• config/src/lib.rs (or wherever WorkflowConfig is defined) — the GithubIssues variant showing what fields are actually accepted

QA plan

1. Copy hub.toml.example to ~/.config/hub/hub.toml (or the config path for your device).
2. Uncomment the assigned_only = true line under a [[workflows]] block with name = "github-issues".
3. Run just cli or just tui.
4. Expect the config to load without error.
5. Before this fix: expect a deserialization error naming assigned_only as an unknown field.

Done when

Every field shown in hub.toml.example is accepted by the config parser without error, or is clearly annotated as a planned but unimplemented option.