v2.70.1 — telemetry privacy fix
Privacy fix: a legacy config.json no longer silently re-enables telemetry
A pre-v2.9.2 install left ~/.great_cto/config.json with { "telemetry": true }. v2.70.0's opt-in resolver honored that stale flag and silently re-enabled collection on upgrade — without a fresh, informed opt-in. Fixed: only the new ~/.great_cto/telemetry.json (or GREAT_CTO_TELEMETRY=on) enables telemetry; the legacy fallback is gone. +1 regression test (8/8).