fix: expose pcid handoff to spawned drivers

Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-openagent)

Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>

local/patches/base/P4-pcid-public-client-channel.patch

@@ -0,0 +1,8 @@
+--- a/drivers/pcid/src/driver_interface/mod.rs
++++ b/drivers/pcid/src/driver_interface/mod.rs
+@@ -310,4 +310,4 @@ impl PciFunctionHandle {
+-    fn connect_default() -> Self {
++    pub fn connect_default() -> Self {
+         let channel_fd = match env::var("PCID_CLIENT_CHANNEL") {
+             Ok(channel_fd) => channel_fd,
+             Err(err) => {

local/patches/base/P4-pcid-spawner-pci-coordinate-env.patch

@@ -0,0 +1,37 @@
+--- a/drivers/pcid-spawner/src/main.rs
++++ b/drivers/pcid-spawner/src/main.rs
+@@ -54,11 +54,12 @@ fn main() -> Result<()> {
+             }
+         };
+ 
+-        let full_device_id = handle.config().func.full_device_id;
++        let func = handle.config().func;
++        let full_device_id = func.full_device_id;
+ 
+         log::debug!(
+             "pcid-spawner enumerated: PCI {} {}",
+-            handle.config().func.addr,
++            func.addr,
+             full_device_id.display()
+         );
+ 
+@@ -67,7 +68,7 @@ fn main() -> Result<()> {
+             .iter()
+             .find(|driver| driver.match_function(&full_device_id))
+         else {
+-            log::debug!("no driver for {}, continuing", handle.config().func.addr);
++            log::debug!("no driver for {}, continuing", func.addr);
+             continue;
+         };
+ 
+@@ -91,6 +92,10 @@ fn main() -> Result<()> {
+ 
+         let channel_fd = handle.into_inner_fd();
+         command.env("PCID_CLIENT_CHANNEL", channel_fd.to_string());
++        command.env("PCID_SEGMENT", format!("{:04x}", func.addr.segment()));
++        command.env("PCID_BUS", format!("{:02x}", func.addr.bus()));
++        command.env("PCID_DEVICE", format!("{:02x}", func.addr.device()));
++        command.env("PCID_FUNCTION", format!("{}", func.addr.function()));
+ 
+         #[allow(deprecated, reason = "we can't yet move this to init")]
+         daemon::Daemon::spawn(command);