v0.0.21: FC-CRATE-1 — make warzone-protocol importable standalone

Replaced workspace dep inheritance with explicit versions in
warzone-protocol/Cargo.toml. The crate now builds both as a
workspace member AND standalone.

WZP can now import warzone-protocol directly:
  warzone-protocol = { path = "../featherChat/warzone/crates/warzone-protocol" }

This means WZP can delete its mirrored identity/crypto code and use:
- warzone_protocol::identity::{Seed, IdentityKeyPair, PublicIdentity}
- warzone_protocol::crypto::{hkdf_derive, aead_encrypt, aead_decrypt}
- warzone_protocol::ethereum::{derive_eth_identity, EthAddress}
- warzone_protocol::message::{WireMessage, CallSignalType}
- warzone_protocol::types::Fingerprint

Single source of truth for identity derivation — no more HKDF mismatches.

28/28 tests pass. Zero warnings.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

warzone/Cargo.lock

@@ -2789,7 +2789,7 @@ dependencies = [
 
 [[package]]
 name = "warzone-client"
-version = "0.0.20"
+version = "0.0.21"
 dependencies = [
  "anyhow",
  "argon2",
@@ -2822,7 +2822,7 @@ dependencies = [
 
 [[package]]
 name = "warzone-mule"
-version = "0.0.20"
+version = "0.0.21"
 dependencies = [
  "anyhow",
  "clap",
@@ -2831,7 +2831,7 @@ dependencies = [
 
 [[package]]
 name = "warzone-protocol"
-version = "0.0.20"
+version = "0.0.21"
 dependencies = [
  "base64",
  "bincode",
@@ -2856,7 +2856,7 @@ dependencies = [
 
 [[package]]
 name = "warzone-server"
-version = "0.0.20"
+version = "0.0.21"
 dependencies = [
  "anyhow",
  "axum",
@@ -2883,7 +2883,7 @@ dependencies = [
 
 [[package]]
 name = "warzone-wasm"
-version = "0.0.20"
+version = "0.0.21"
 dependencies = [
  "base64",
  "bincode",