Bridge child sessions gain auto-mode permission defaulting and a resume max-age setting

What

• New logic classifies a spawned bridge child session as an "rc-child" and decides whether to force permissions.defaultMode: 'auto' for it, passing an autoMode.environment list via a new --settings= argument to the spawned subprocess. Whether this fires at all, and whether it can override the user's own settings, are each controlled by separate gates.
• When a bridge worker resumes an interrupted turn after a rebound worker epoch, it now also sets a new CLAUDE_CODE_RESUME_INTERRUPTED_TURN_MAX_AGE_MS environment variable (only alongside the existing CLAUDE_CODE_RESUME_INTERRUPTED_TURN, and only when the resumed turn is bound). The auto-mode settings argument is computed and passed as --settings= before other server config arguments.

Why This is infrastructure for how Claude Code's bridge feature spawns and resumes child sessions: it controls whether a spawned child defaults to unattended "auto" permission mode and how stale an interrupted turn can be before it's no longer eligible to resume.