docs(agents): add TORCH protocol documentation

TORCH (Task Orchestration via Relay-Coordinated Handoff) is the name
for the Nostr-based distributed task locking system used to coordinate
multi-agent development.

Adds docs/agents/TORCH.md covering:
- Protocol overview with sequence diagram
- NIP-78 event schema with tag breakdown
- Ephemeral key lifecycle and why no secrets are needed
- Race detection mechanism
- Auto-expiration via NIP-40
- Configuration reference
- Architecture diagram
- Path toward a generalizable drop-in package for any repo

Also references TORCH by name in AGENTS.md, scheduler-flow.md,
nostr-lock.mjs header, and CLAUDE.md key documentation table.

https://claude.ai/code/session_01BpDsVSAkVWtJLnfKxsB9ib

scripts/agent/nostr-lock.mjs

@@ -2,11 +2,13 @@
 
 // scripts/agent/nostr-lock.mjs
 //
-// Nostr-based distributed task locking for multi-agent coordination.
+// TORCH — Task Orchestration via Relay-Coordinated Handoff
 //
+// Decentralized task locking for multi-agent development using Nostr.
 // Each lock generates a fresh ephemeral keypair and discards it.
-// Locks auto-expire via NIP-40 — no cleanup needed.
-// Other agents discover locks by querying relays for bitvid lock events.
+// Locks auto-expire via NIP-40 — no cleanup, no tokens, no secrets.
+//
+// See docs/agents/TORCH.md for the full protocol documentation.
 //
 // Commands:
 //   check  --cadence <daily|weekly>                  JSON list of locked agents