nordisk/dwarves

dwarves — the Forge(live) run-picker

A follow-up deferred in 3e082eb (the GetRunReport + dwarves-embed live tab): the live pane rendered only the newest run (or the one pinned via $DWARVES_RUN_ID). This adds a run-picker — a dropdown of recent runs — so a viewer chooses which historized run to render, live, from the UI. No proto change (the History RPC already carried the run list), additive (unpinned still ⇒ newest), and it reuses the same GetRunReport → ForgePipelineAdapter → PipelineView path.

The one-call fetch (dwarves-embed::fetch_forge_split)

The pane's fetch returns both halves in a SINGLE connection, with the two legs split:

• fetch_forge_split(endpoint, token, run_id, history_limit) -> Result<ForgeFetch> — one History(limit) call feeds both the picker list and newest-run selection (when run_id is unpinned), then one GetRunReport(id) fetches the selected run. ForgeFetch { runs: Vec<RunRow>, report: Result<RunReport> } keeps the legs apart: the outer Err is the LIST leg failing (couldn't connect / History errored ⇒ genuinely unavailable); a report: Err(…) is only the SELECTED run's report failing (a bad pin / a run that vanished) while the run list is fresh.
• fetch_forge(…) -> (Vec<RunRow>, RunReport) folds the split back to the strict all-or-nothing pair (a report error ⇒ overall Err); fetch_run_report is a thin wrapper over that. No twin — three functions, one fetch body.

Report-error resilience — a bad pin never blanks the picker

When History succeeds but the pinned run's GetRunReport fails, the pane lands in a distinct report_error Conn state instead of collapsing to unavailable:

• apply_fetch(Result<ForgeFetch>) (split out of refresh so the transitions are drivable headless) repopulates runs from the fresh History list before looking at the report — so the dropdown stays usable to switch to a working run. Only when the forge has no runs at all does a report error stay the plain unavailable/no-runs state.
• The control strip shows an amber "run <id> unavailable — pick another run" (the error on hover); state_json.status == "report_error" with run_count intact. Picking a good run re-fetches and clears the error. Previously the whole result was discarded on a report error, throwing the freshly-fetched list away — the fix that closed the last run-picker deferral.

The pure mapping (run_picks_from_wire)

• RunPick { run_id, pipeline, status } — one dropdown entry, Serialize for state_json.
• run_picks_from_wire(&[RunRow]) -> Vec<RunPick> — pure, order-preserving (newest-first, as the server returns), so the picker list is unit-testable with no server.

The pane (ForgePanel)

• Two new fields: runs: Vec<RunPick> (the offered list) + history_limit: u32 (DEFAULT_HISTORY_LIMIT = 20). refresh() → apply_fetch() repopulates runs from the fresh History list whenever the list leg succeeds; a dead-server fetch error leaves the list as-is (a blip doesn't blank the dropdown), and a report-only error keeps the fresh list (the report_error state above).
• UI: an egui::ComboBox in the control strip — ● newest plus one entry per run (run_id · pipeline · status). Selecting an entry pins its run_id and re-fetches; ● newest clears the pin. The click drives the exact same seam a robot uses.
• state_json gains selected_run_id (the pin; null ⇒ newest), runs, run_count, history_limit — the robot-observable picker surface.
• update_json already pinned {"run_id": "…"} ("" ⇒ newest); now also {"history_limit": N} resizes the list. Both re-fetch.

Why this shape

• Reuse, no twin (L5). fetch_run_report becomes a wrapper over fetch_forge; the render path (GetRunReport → ForgePipelineAdapter::from_report → PipelineView) is untouched. No new RPC, no new viewer.
• Additive (L2). The default (unpinned ⇒ newest, auto-poll) is byte-for-byte the prior behaviour; the picker is purely additional surface.
• Robot-tested (L4). The picker (list + pin + clear) and the report_error recovery drive headless over state_json (apply_fetch → state_json), closing the coverage gap on the newest UI surface (the live-forge tab was mounted but not yet robot-ledgered).

Deferred

• The picker lists History(limit) runs (default 20) — no paging / infinite scroll.
• No live-search/filter box over the list yet (fine at 20; add a filter if limit grows).
• Selection is by run_id only; a richer label (project + finished-at) is cosmetic.