feat(telemetry): add local agent efficiency metrics

shared/hooks/scripts/record-compact.sh

@@ -1,6 +1,5 @@
 #!/usr/bin/env bash
 set -euo pipefail
 root=$(cd -- "$(dirname -- "${BASH_SOURCE[0]}")/../.." && pwd)
-mkdir -p "$root/.ai-session"
-printf '{"event":"compact","timestamp":"%s"}\n' "$(date -u +%Y-%m-%dT%H:%M:%SZ)" >> "$root/.ai-session/telemetry.jsonl"
+[ "${AI_CONFIG_TELEMETRY:-1}" = 0 ] || { mkdir -p "$root/.ai-session" && printf '{"event":"compact","timestamp":"%s"}\n' "$(date -u +%Y-%m-%dT%H:%M:%SZ)" >> "$root/.ai-session/telemetry.jsonl"; [ "$(wc -c < "$root/.ai-session/telemetry.jsonl")" -le 1048576 ] || mv -f "$root/.ai-session/telemetry.jsonl" "$root/.ai-session/telemetry.jsonl.1"; }
 python3 "$root/hooks/scripts/session-state.py" --hook