chore(app-server-protocol): split v2 API definitions into modules (#21251)

## Why

`codex-rs/app-server-protocol/src/protocol/v2.rs` had grown into a
single ~12k-line definition file for the entire app-server v2 API.

This is purely a mechanical refactor to break up the monolithic `v2.rs`
file that contains all app-server API v2 types into more modular files,
grouped by resource (e.g. account, thread, turn, etc.).

`just write-app-server-schema` shows no real changes, so we can be sure
that this is purely an internal organizational change.

## What changed

- Replaced the monolithic `protocol/v2.rs` with a `protocol/v2/` module
tree and a small `mod.rs` that only declares and reexports modules.
- Grouped v2 API definitions by conceptual owner, including `account`,
`apps`, `collaboration_mode`, `command_exec`, `config`, `device_key`,
`experimental_feature`, `feedback`, `fs`, `hook`, `item`, `mcp`,
`model`, `notification`, `permissions`, `plugin`, `process`, `realtime`,
`review`, `thread`, `thread_data`, `turn`, and `windows_sandbox`.
- Moved v2 tests into `protocol/v2/tests.rs` so `mod.rs` stays small.
- Kept shared protocol helpers in `protocol/v2/shared.rs`, including the
enum mirroring macro and common cross-resource types.
- Co-located resource-specific notifications and server-request payloads
with the modules that own those resources.
- Regenerated app-server protocol schema fixtures. The schema diffs are
non-semantic newline-only changes after the refactor.

## Verification

- `cargo check -p codex-app-server-protocol`
- `cargo test -p codex-app-server-protocol`
- `just write-app-server-schema`

codex-rs/app-server-protocol/src/protocol/v2/feedback.rs

@@ -0,0 +1,29 @@
+use schemars::JsonSchema;
+use serde::Deserialize;
+use serde::Serialize;
+use std::collections::BTreeMap;
+use std::path::PathBuf;
+use ts_rs::TS;
+
+#[derive(Serialize, Deserialize, Debug, Clone, PartialEq, JsonSchema, TS)]
+#[serde(rename_all = "camelCase")]
+#[ts(export_to = "v2/")]
+pub struct FeedbackUploadParams {
+    pub classification: String,
+    #[ts(optional = nullable)]
+    pub reason: Option<String>,
+    #[ts(optional = nullable)]
+    pub thread_id: Option<String>,
+    pub include_logs: bool,
+    #[ts(optional = nullable)]
+    pub extra_log_files: Option<Vec<PathBuf>>,
+    #[ts(optional = nullable)]
+    pub tags: Option<BTreeMap<String, String>>,
+}
+
+#[derive(Serialize, Deserialize, Debug, Clone, PartialEq, JsonSchema, TS)]
+#[serde(rename_all = "camelCase")]
+#[ts(export_to = "v2/")]
+pub struct FeedbackUploadResponse {
+    pub thread_id: String,
+}