fix(code-mappings): Address PR feedback on help text and unwrap usage

Add descriptive help text explaining what code mappings are and how they
work. Replace unwrap with expect for the required path argument.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: romtsn

src/commands/code_mappings/upload.rs

@@ -13,7 +13,7 @@ struct CodeMapping {
 
 pub fn make_command(command: Command) -> Command {
     command
-        .about("Upload code mappings for a project from a JSON file.")
+        .about("Upload code mappings for a project from a JSON file. Each mapping pairs a stack trace root (e.g. com/example/module) with the corresponding source path in your repository (e.g. modules/module/src/main/java/com/example/module).")
         .arg(
             Arg::new("path")
                 .value_name("PATH")
@@ -36,8 +36,9 @@ pub fn make_command(command: Command) -> Command {
 }
 
 pub fn execute(matches: &ArgMatches) -> Result<()> {
-    #[expect(clippy::unwrap_used, reason = "path is a required argument")]
-    let path = matches.get_one::<String>("path").unwrap();
+    let path = matches
+        .get_one::<String>("path")
+        .expect("path is a required argument");
     let data = fs::read(path).with_context(|| format!("Failed to read mappings file '{path}'"))?;
 
     let mappings: Vec<CodeMapping> =

tests/integration/_cases/code_mappings/code-mappings-help.trycmd

@@ -7,7 +7,9 @@ repository, enabling source context and code linking in Sentry.
 Usage: sentry-cli[EXE] code-mappings [OPTIONS] <COMMAND>
 
 Commands:
-  upload  Upload code mappings for a project from a JSON file.
+  upload  Upload code mappings for a project from a JSON file. Each mapping pairs a stack trace root
+          (e.g. com/example/module) with the corresponding source path in your repository (e.g.
+          modules/module/src/main/java/com/example/module).
   help    Print this message or the help of the given subcommand(s)
 
 Options:

tests/integration/_cases/code_mappings/code-mappings-no-subcommand.trycmd

@@ -7,7 +7,9 @@ repository, enabling source context and code linking in Sentry.
 Usage: sentry-cli[EXE] code-mappings [OPTIONS] <COMMAND>
 
 Commands:
-  upload  Upload code mappings for a project from a JSON file.
+  upload  Upload code mappings for a project from a JSON file. Each mapping pairs a stack trace root
+          (e.g. com/example/module) with the corresponding source path in your repository (e.g.
+          modules/module/src/main/java/com/example/module).
   help    Print this message or the help of the given subcommand(s)
 
 Options:

tests/integration/_cases/code_mappings/code-mappings-upload-help.trycmd

@@ -1,7 +1,9 @@
 ```
 $ sentry-cli code-mappings upload --help
 ? success
-Upload code mappings for a project from a JSON file.
+Upload code mappings for a project from a JSON file. Each mapping pairs a stack trace root (e.g.
+com/example/module) with the corresponding source path in your repository (e.g.
+modules/module/src/main/java/com/example/module).
 
 Usage: sentry-cli[EXE] code-mappings upload [OPTIONS] <PATH>