Reflection follow-up: rewrite missing substrate file SESSION-LEDGER-PROTOCOL.md

Missing path: ~/shared-knowledge/SESSION-LEDGER-PROTOCOL.md Referenced in: AGENTS.md lines 146 and 245. AGENTS.md says "Read SESSION-LEDGER-PROTOCOL.md — follow it exactly" and describes two trigger classes: (1) active work events (sub-agents spawned, PRs touched, DMs sent) requiring real-time append to memory/YYYY-MM-DD.md, and (2) state-transition events (RESOLVED-ESCALATIONS writes, PENDING-ASKS moves, fleet-task status changes) also requiring same-turn appends. NOTE: This file was previously identified as missing on 6/13 and reportedly rewritten then. It is missing again as of 6/14. Rewrite should be durable — check if shared-knowledge nightly pull cron overwrote the file or if the 6/13 write was not to the correct path.