feat: add markdown editing mode

Signed-off-by: kjuulh <contact@kjuulh.io>

crates/hyperlog-tui/Cargo.toml

@@ -17,6 +17,10 @@ serde_json.workspace = true
 itertools.workspace = true
 tonic.workspace = true
 futures.workspace = true
+sha2.workspace = true
+uuid.workspace = true
+hex.workspace = true
+toml.workspace = true
 
 ratatui = "0.26.2"
 crossterm = { version = "0.27.0", features = ["event-stream"] }