[iamnbutler]

Closes #138.

Summary

The real cause is that a Chromium <select> menu closes between tool calls. Clicking an item or using AXPick from a later snapshot therefore goes stale (SNAPSHOT_STALE). The fix is to pick with one desktop_key call while the select has keyboard focus: keys: [down (opens the menu), down × n, enter], where n is the target option's index minus the current option's index. This works in the background.

• docs/recipes.md: new recipe "Pick from a native select in a browser". It covers focusing the select (Tab, or a click, which also opens the menu), counting n from the options an open menu lists, the single key call, and reading back the AXPopUpButton value. desktop_activate is mentioned only as a fallback when the value didn't change. Separators and disabled items are marked (unverified). The web form recipe step now points Chromium browsers to the new recipe.
• docs/tools.md and the desktop_set_value / desktop_element_action descriptions in src/tools.ts keep click + AXPick for native pop-up buttons and point Chromium <select> to the single desktop_key call.
• CHANGELOG [Unreleased] entry.

An earlier revision downgraded desktop_key to unknown for background Chromium apps. Live checks disproved that premise, so it was removed. There are no code or native changes now, only docs and tool descriptions.

Live evidence

Setup: isolated Chrome, a local page with an <input> and a <select>, Chrome in the background with Preview frontmost, installed host 0.14.1.

1. Background desktop_key x ×3 into a focused Chrome text input: the keys landed (xxx). The Fill password fields: from the Keychain by reference, or agent-supplied text with approval #117 spike also saw background keys land in a Chrome password field.
2. Background desktop_key with keys [tab, down]: focus moved to the select and its menu opened (AXMenu plus 5 AXMenuItems in the next snapshot).
3. desktop_element_action AXPick on an item from that snapshot: refused with SNAPSHOT_STALE, which reproduces the issue. The next inspect showed the menu had closed by itself, and the select kept focus.
4. One background desktop_key call with keys [down, down, down, down, enter]: the select's AXPopUpButton value read back "English (U.S.)" (the 4th item). Chrome never came forward.

Testing

• npm test and npm run check pass.

Follow-up

• A desktop_choose tool, or extending desktop_select, for AXPopUpButton: open the menu, find the item by title, and pick it in one call. This is out of scope here.