feat: add axon CLI for pub/sub; fix relay hijack context bug

- cmd/axon: new CLI module with keygen, pub, and req subcommands
  - keygen: generate Ed25519 keypair, print hex seed and pubkey
  - pub: sign and publish an event; accepts --kind, --content, --tag
  - req: query/stream events as JSON lines; accepts --kind, --author,
    --tag, --since, --until, --limit, --stream
  - key loaded from --key flag or AXON_KEY env var

- relay/websocket: add Dial() for client-side WebSocket handshake
  (ws:// and wss://, RFC 6455 masking via client:true)

- relay/server: fix broken-pipe on auth by switching hijacked conn
  goroutine from r.Context() to context.Background(); r.Context() is
  cancelled by net/http immediately after Hijack is called

1 files changed, 1 insertions, 0 deletions

diff --git a/go.work b/go.work
index 47a23cd..09ca901 100644
--- a/go.work
+++ b/go.work
@@ -3,4 +3,5 @@ go 1.25.5
 use (
         .
         ./relay
+        ./cmd/axon
 )