pi-processes v0.12.0

860d98e: Add an adopt API so other extensions can hand an already-running child process over to the manager. ProcessManager.adopt(name, command, cwd, child, { initialStdout, initialStderr, startTime }) registers an externally spawned child (detached process group, piped stdio) as a managed process, and the new processes:command:adopt event-bus channel exposes it cross-extension. Adopted processes get the full managed lifecycle: log capture (including output produced before the handover), liveness watching, kill/stop, notifications, and dock//ps visibility. This enables tools like a bash override that moves a long-running foreground command into the background without losing output.