refactor: put every filesystem write behind one module

Cargo.lock

@@ -9,6 +9,7 @@ dependencies = [
  "anyhow",
  "clap",
  "clap_complete",
+ "fs-err",
  "serde_json",
  "shlex",
 ]
@@ -69,6 +70,12 @@ version = "1.0.104"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "330a5ed07fa54e4702c9d6c4174f74427fc0ef6e214bbd677ae50a5099946470"
 
+[[package]]
+name = "autocfg"
+version = "1.5.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f2032f911046de80f0a198e0901378627c33f59ea0ac00e363d481118bd70a53"
+
 [[package]]
 name = "clap"
 version = "4.6.6"
@@ -124,6 +131,15 @@ version = "1.0.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "1d07550c9036bf2ae0c684c4297d503f838287c83c53686d05370d0e139ae570"
 
+[[package]]
+name = "fs-err"
+version = "3.3.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b91aa448ca50d7e79433bdf3ee8d99215430d2ec02ade5aefab2a073a1822e8a"
+dependencies = [
+ "autocfg",
+]
+
 [[package]]
 name = "heck"
 version = "0.5.0"