feat: add Vec<ParsedCommand> to ExecApprovalRequestEvent (#5222)

This adds `parsed_cmd: Vec<ParsedCommand>` to `ExecApprovalRequestEvent`
in the core protocol (`protocol/src/protocol.rs`), which is also what
this field is named on `ExecCommandBeginEvent`. Honestly, I don't love
the name (it sounds like a single command, but it is actually a list of
them), but I don't want to get distracted by a naming discussion right
now.

This also adds `parsed_cmd` to `ExecCommandApprovalParams` in
`codex-rs/app-server-protocol/src/protocol.rs`, so it will be available
via `codex app-server`, as well.

For consistency, I also updated `ExecApprovalElicitRequestParams` in
`codex-rs/mcp-server/src/exec_approval.rs` to include this field under
the name `codex_parsed_cmd`, as that struct already has a number of
special `codex_*` fields. Note this is the code for when Codex is used
as an MCP _server_ and therefore has to conform to the official spec for
an MCP elicitation type.

codex-rs/protocol/src/protocol.rs

@@ -1178,6 +1178,7 @@ pub struct ExecApprovalRequestEvent {
     /// Optional human-readable reason for the approval (e.g. retry without sandbox).
     #[serde(skip_serializing_if = "Option::is_none")]
     pub reason: Option<String>,
+    pub parsed_cmd: Vec<ParsedCommand>,
 }
 
 #[derive(Debug, Clone, Deserialize, Serialize, TS)]