Initial workspace: scaffold + constitution + spec documents

Rust workspace with 5 crates (mesh-types, mesh-crypto, mesh-network,
mesh-validator, mesh-wallet), PROJECT_CONSTITUTION.md for CHORUS
automated ingestion, and the full MESH protocol specification suite.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

.gitignore

@@ -0,0 +1,5 @@
+/target
+Cargo.lock
+*.swp
+*.swo
+.DS_Store