chore: update validator crate to 0.20.0 and add .idea to .gitignore

[Lotchouang]

🚀 Summary

• Ignore IDE files by adding /.idea to .gitignore
• Upgrade the validator crate from 0.18.0 → 0.20.0 (with derive feature)
• Adjust Rocket form-validation glue to match Validator 0.20’s API:
  • Import NameBuf from rocket::form::name
  • Build form errors using an owned NameBuf instead of a borrowed Cow

---

📝 Changes

1. .gitignore

 /target
+/.idea

• Prevent IDE-specific files from being committed.

2. Cargo.toml

[dependencies]
- validator = { version = "0.18.0", features = ["derive"] }
+ validator = { version = "0.20.0", features = ["derive"] }

• Bump to the latest validator release for bug fixes and improved derive macros.

3. src/lib.rs

-use rocket::{
-    data::{Data, FromData, Outcome as DataOutcome},
-    form,
-    form::{DataField, FromForm, ValueField},
-    http::Status,
-    outcome::Outcome,
-};
+use rocket::{
+    data::{Data, FromData, Outcome as DataOutcome},
+    form,
+    form::name::NameBuf,
+    form::{DataField, FromForm, ValueField},
+    http::Status,
+    outcome::Outcome,
+};

Form-Validation Impl Update

 impl<'r, T: Validate + FromForm<'r>> FromForm<'r> for Validated<T> {
     // …
     .map(|e| form::Error {
-        name: Some(e.0.into()),
-        kind: form::error::ErrorKind::Validation(std::borrow::Cow::Borrowed(e.0)),
+        name: Some(NameBuf::from(e.0.clone()).into_owned()),
+        kind: form::error::ErrorKind::Validation(e.0),
         value: None,
         entity: form::error::Entity::Value,
     })
     // …
 }

Switch from Cow::Borrowed(&str) to fully owned NameBuf.

Simplify the Validation payload in line with Validator 0.20’s API.