New global Side card setting `agentOpenTools` (default off, 常规 group):
when enabled, one `sidebar_open` tool is injected into the model so it can
actively open a local file, a local folder (tree rooted there), or an
HTTP(S) page in the calling session's sidebar.
- host: AgentOpenRegistry + registerOpenTool (src/agent-opens.ts); the tool
classifies http(s) URLs / stat-driven file/folder paths, refuses other
schemes, resolves relative paths against the session cwd, and reports
target-tab-disabled instead of silently no-oping. Gated like
agentTerminalTools (register/drain on settings watch).
- delivery: /sidebar/ws/agent-opens push (consume-on-send queue, replay on
attach); the tool result reports `delivered` so queued opens for
non-active sessions are honest.
- client: Sidebar subscribes and routes pushes to editor (file), folder
window (meta.dir, tree rooted at the folder — EditorHost), or browser
(URL) tabs; settings row in 常规 + 20 locale dictionaries.
- tests: agent-opens registry/tool spec, smoke gating + WS route list,
prefs/plugin-shape defaults, editor-host folder window, side-card rows.
- docs: design doc, AGENTS.md key lists + reference, README feature bullets.
