feat(proxy): add crash-safe recovery watchdog

Cargo.toml

@@ -1,5 +1,5 @@
 [workspace]
-members = ["crates/capture-ipc", "crates/gateway", "crates/prompt-ir"]
+members = ["crates/capture-ipc", "crates/gateway", "crates/prompt-ir", "crates/proxy-recovery"]
 resolver = "3"
 
 [workspace.package]
@@ -18,3 +18,4 @@ serde_json = "1.0"
 tokio = { version = "1.45", features = ["io-util", "macros", "net", "rt-multi-thread", "signal", "sync", "time"] }
 tokio-stream = "0.1"
 url = "2.5"
+windows-sys = { version = "0.61", features = ["Win32_Storage_FileSystem"] }

README.md

@@ -19,6 +19,8 @@ Rust crate 位于 `crates/prompt-ir`，公开 JSON Schema 位于 `schemas/prompt
 
 捕获 sidecar 位于 `sidecars/mitmproxy`，跨进程契约位于 `crates/capture-ipc`，公开 CaptureEnvelope Schema 位于 `schemas/capture-envelope/v0.1.schema.json`。sidecar 的安装、测试与打包命令见 [`sidecars/mitmproxy/README.md`](./sidecars/mitmproxy/README.md)。
 
+系统代理事务与独立恢复 watchdog 的平台无关核心位于 `crates/proxy-recovery`；当前使用文件 backend 做强杀故障注入，真实 Windows/macOS backend 尚在开发。
+
 启动 Gateway Spike：
 
 ```powershell

crates/proxy-recovery/Cargo.toml

@@ -0,0 +1,13 @@
+[package]
+name = "codeischeap-proxy-recovery"
+version = "0.1.0"
+edition.workspace = true
+rust-version.workspace = true
+description = "Transactional system proxy recovery core for CodeIsCheap"
+
+[dependencies]
+serde.workspace = true
+serde_json.workspace = true
+
+[target.'cfg(windows)'.dependencies]
+windows-sys.workspace = true

crates/proxy-recovery/README.md

@@ -0,0 +1,13 @@
+# Proxy recovery core
+
+This crate owns the transaction state machine used before CodeIsCheap changes system proxy settings.
+
+1. Read the exact original settings.
+2. Persist an armed recovery journal.
+3. Spawn an independent watchdog and wait for its `ready` handshake.
+4. Apply the desired proxy settings.
+5. On normal shutdown, restore and disarm the watchdog.
+6. On owner-process death, pipe EOF makes the watchdog restore its in-memory snapshot.
+7. On the next startup, an armed journal provides a second recovery path.
+
+The included file backend exists only for deterministic crash injection. Production Windows and macOS backends, private journal-directory permissions, and platform notifications are separate work; `SPIKE-003` remains in progress until those backends pass real setting/restore experiments.

crates/proxy-recovery/src/bin/proxy-recovery-spike.rs

@@ -0,0 +1,42 @@
+use std::env;
+use std::fs;
+use std::path::PathBuf;
+use std::thread;
+use std::time::Duration;
+
+use codeischeap_proxy_recovery::{FileProxyBackend, ProxySession, ProxySettings};
+
+fn main() -> Result<(), Box<dyn std::error::Error>> {
+    let mut arguments = env::args_os().skip(1);
+    if arguments.next().as_deref() != Some("hold".as_ref()) {
+        return Err("usage: proxy-recovery-spike hold <state> <journal> <ready> <watchdog>".into());
+    }
+    let state = next_path(&mut arguments, "state")?;
+    let journal = next_path(&mut arguments, "journal")?;
+    let ready = next_path(&mut arguments, "ready")?;
+    let watchdog = next_path(&mut arguments, "watchdog")?;
+    if arguments.next().is_some() {
+        return Err("unexpected proxy-recovery-spike argument".into());
+    }
+
+    let desired = ProxySettings::Manual {
+        http_proxy: "http://127.0.0.1:3210".to_owned(),
+        https_proxy: "http://127.0.0.1:3210".to_owned(),
+        bypass: vec!["localhost".to_owned(), "127.0.0.1".to_owned()],
+    };
+    let _session = ProxySession::begin(FileProxyBackend::new(state), desired, journal, watchdog)?;
+    fs::write(ready, b"ready\n")?;
+    loop {
+        thread::sleep(Duration::from_secs(60));
+    }
+}
+
+fn next_path(
+    arguments: &mut impl Iterator<Item = std::ffi::OsString>,
+    name: &str,
+) -> Result<PathBuf, Box<dyn std::error::Error>> {
+    arguments
+        .next()
+        .map(PathBuf::from)
+        .ok_or_else(|| format!("missing {name} path").into())
+}

crates/proxy-recovery/src/bin/proxy-watchdog.rs

@@ -0,0 +1,20 @@
+use std::env;
+use std::path::PathBuf;
+
+use codeischeap_proxy_recovery::run_watchdog;
+
+fn main() -> Result<(), Box<dyn std::error::Error>> {
+    let mut arguments = env::args_os().skip(1);
+    if arguments.next().as_deref() != Some("--journal".as_ref()) {
+        return Err("usage: proxy-watchdog --journal <path>".into());
+    }
+    let journal = arguments
+        .next()
+        .map(PathBuf::from)
+        .ok_or("missing journal path")?;
+    if arguments.next().is_some() {
+        return Err("unexpected proxy-watchdog argument".into());
+    }
+    run_watchdog(&journal)?;
+    Ok(())
+}