Session pin resolution now detects renamed sessions and reports contested identity

What

• The cross-session messaging telemetry event (uds, used when sending messages to other Claude Code sessions) gains two new boolean fields: whether the target session restarted since it was pinned, and whether its identity was contested (ambiguous) when resolving the pin.
• New logic detects when a session referenced by an earlier send_message pin has since been renamed on the same machine (matched via socket identity and former names), and surfaces a renamedTo hint.
• When a session can't be reached, the error message now appends a note like "A session now named '' reports it as a former name (renamed)" instead of just failing outright, and pin resolution can follow a rename using identity-contested/pin-id reconciliation.

Why Previously, sending a message to a session that had since been renamed could silently fail. Now Claude Code detects the rename, reports the ambiguity, and gives a clearer error pointing to the session's new name.