ADR 0026: Loading, failure and log feedback for extensions

Context #

An extension that blocked in on_query on a slow or failing request left the launcher blank: no row, no status, and the only trace was a line in a log file. A folder that failed to load, such as a min_zagros check against a dev build, was not in the manager at all.

Decision #

• The catalog tells the UI which tier-1 providers it is still waiting for after 300 ms (Snapshot.Slow) and, on the last snapshot, which ones gave nothing and why (Snapshot.Problems: budget exceeded, or the reason from the optional core.Failer). No extension code is needed.
• ext.LogBuffer keeps 100 entries per extension in memory by wrapping Options.Log. Nothing is written to disk. The manager shows each extension's lines, and the tray item "Log console" opens a console window (zagros logs --window, a separate process so closing it cannot stop the launcher) that streams all of them live from the launcher over a local socket (<data dir>/logs.sock). The standard logger is routed into the same buffer as source zagros; the last 2000 lines are kept.
• Folders that fail to load are listed as broken:<folder> and can be removed.
• Builds that are not a semver release never fail min_zagros.
• task() and item(pending = True) stay the way to show a loading row. No new extension API and no permission.

Consequences #

Every query to a slow extension may produce one more snapshot at 300 ms. The status line is plain text; it does not say which request is slow, only which extension.