Human-facing window selection: status-bar target, Select Target Window quick-pick, optional pid on path-less tools

[MatthiasHertelArm]

Observed: "The CMSIS bridge sees two VS Code windows, so it refused to guess." The agent had to pin the CDA-Testdrive window itself; the user had no UI to do it.

State today: the router already refuses ties with an error that lists every candidate (pid, folders, active session) and names select_debug_window (routingDebuggingHandler.ts:97-119); list_debug_windows / select_debug_window({ pid | workspaceFolder }) exist (debugMCPServer.ts:799-820). What is missing:

• No human-facing affordance. No status-bar item, no quick-pick; the only showQuickPick in the extension picks a launch configuration. The user cannot see which window is router/worker or which window an agent session is pinned to.
• No per-call selector on the path-less tools (cmsis_action, flash, reset, serial): the only way to aim them is the per-session pin.

Proposed:

• Status-bar item "CDA · router | worker · target: " with a Select Target Window command that sets a default pin the router honours when the ladder ties (explicit select_debug_window still wins).
• Optional pid / workspaceFolder argument on cmsis_action, flash, reset and the serial tools.
• Keep the candidate list in the error payload (it is already there; make it structured per the structured-result issue).

Priority: P2 — every multi-window user hits it.