Why

codex.task.compact only distinguished local vs remote, which made it hard to answer simple counter questions in Statsig. Manual /compact and automatic compaction were collapsed together, and the legacy remote path was also collapsed with remote_compaction_v2.

What Changed

• route codex.task.compact through a shared helper in core/src/tasks/mod.rs
• add a manual=true|false tag so manual and automatic compaction can be counted separately
• split the remote tag into remote and remote_v2
• emit the metric from the inline auto-compaction path in core/src/session/turn.rs as well as the manual CompactTask path in core/src/tasks/compact.rs
• add focused unit coverage for the new tag shapes in core/src/tasks/mod_tests.rs

Verification

• added unit coverage in core/src/tasks/mod_tests.rs covering manual remote_v2 tags and automatic local tags