feat: unify webview source into WebviewSource enum with dynamic reload (#22)

Unify CefWebviewUri and InlineHtml into a single WebviewSource enum component, eliminating the dual-component inconsistency where both existed on the same entity
Add ResolvedWebviewUri internal component as a resolution layer between user-facing source and CEF
Support dynamic reload: mutating WebviewSource at runtime automatically navigates the existing browser via browsers.navigate() without recreation
Inline HTML is served via cef://localhost/__inline__/{id} with automatic cleanup on entity despawn

Cargo.toml

@@ -64,6 +64,9 @@ bevy_cef = { workspace = true, features = ["debug"] }
 [target.'cfg(target_os = "macos")'.dependencies]
 objc = { version = "0.2" }
 
+[lints.rust]
+unexpected_cfgs = { level = "warn", check-cfg = ['cfg(feature, values("cargo-clippy"))'] }
+
 [features]
 default = []
 serialize = ["bevy/serialize"]