Improve branch, merge, rebase (#37)

* Always create task branch

* Create new ref

* Save new branch name in DB

* Refactor rebase backend

* Update merging functionality

* Clippy

backend/Cargo.toml

@@ -39,6 +39,7 @@ nix = { version = "0.29", features = ["signal", "process"] }
 openssl-sys = { workspace = true }
 rmcp = { version = "0.1.5", features = ["server", "transport-io"] }
 schemars = "0.8"
+regex = "1.11.1"
 
 [build-dependencies]
 ts-rs = { version = "9.0", features = ["uuid-impl", "chrono-impl"] }