refactor: clear remaining clippy dead-code and cast warnings

Brings `cargo clippy --release --all-targets` and `cargo build --release`
to zero warnings. Three categories:

Truly dead code (deleted):
- OutputInfo.physical_size / .logical_position — copied from PartialOutputInfo
  at construction but never read on OutputInfo; PartialOutputInfo still uses
  them as probe-completion gates
- EncConstructionStage::Streaming.output_info — stored at ->Streaming
  transition, all 9 match arms discard via `..` or `output_info: _`
- State.starting_timestamp — vestigial Phase 1 stub; PTS normalization lives
  in EncState / SwEncState instead (commit 079611a)
- cap_portal::fourcc() const fn — superseded by drm_fourcc::DrmFourcc
- PwThreadCtx.fps — destructured as `fps: _`, never consumed

Lifetime/ownership invariants (kept with #[allow(dead_code)] + reason):
- CapPortal.rt — ashpd caches a zbus::Connection in a process-global
  OnceCell; runtime must outlive CapPortal or the connection hangs
- EncState.hw_device_ctx — root AVHWDeviceContext; consumers hold their
  own ref_clone() but the root ref must stay alive for ownership

False-positive warning (annotated):
- state_portal use AsRawFd — required at FFI boundary but rustc mis-attributes
  the call to OwnedFd's inherent method; E0599 if removed

Cosmetic:
- drop 5 redundant `as *const i32` casts on linesize.as_ptr() in
  avhw/encode.rs and bin/vaapi_import_bench.rs

src/avhw/encode.rs

@@ -173,7 +173,7 @@ impl SwEncEncode {
                 0,
                 self.enc_height as i32,
                 (*self.yuv_frame).data.as_ptr() as *mut *mut u8,
-                (*self.yuv_frame).linesize.as_ptr() as *const i32,
+                (*self.yuv_frame).linesize.as_ptr(),
             );
             if scaled < 0 {
                 bail!("sws_scale failed for software encoder: {scaled}");

src/avhw/hardware.rs

@@ -17,6 +17,10 @@ pub struct EncState {
     enc_video: ff::codec::encoder::video::Video,
     frames_rgb: AvHwFrameCtx,
     video_filter: ff::filter::Graph,
+    // Root AVHWDeviceContext, kept for ownership. Each consumer (encoder,
+    // filter graph, frames ctx) already holds its own ref_clone(); this
+    // field is never read after `new()` but must outlive those clones.
+    #[allow(dead_code)]
     hw_device_ctx: AvHwDevCtx,
     octx: ff::format::context::Output,
     starting_timestamp: Option<i64>,

src/bin/vaapi_import_bench.rs

@@ -587,11 +587,11 @@ fn run_cpu_pipeline(
             ffi::sws_scale(
                 sws_ctx.0,
                 (*sw_frame).data.as_ptr() as *const *const u8,
-                (*sw_frame).linesize.as_ptr() as *const i32,
+                (*sw_frame).linesize.as_ptr(),
                 0,
                 (*sw_frame).height,
                 (*encoder.yuv_frame).data.as_ptr() as *mut *mut u8,
-                (*encoder.yuv_frame).linesize.as_ptr() as *const i32,
+                (*encoder.yuv_frame).linesize.as_ptr(),
             );
         }
         let scale_us = t_scale.elapsed().as_micros() as u64;
@@ -744,11 +744,11 @@ fn run_gpu_pipeline(
             ffi::sws_scale(
                 format_ctx.0,
                 (*sw_nv12).data.as_ptr() as *const *const u8,
-                (*sw_nv12).linesize.as_ptr() as *const i32,
+                (*sw_nv12).linesize.as_ptr(),
                 0,
                 (*sw_nv12).height,
                 (*encoder.yuv_frame).data.as_ptr() as *mut *mut u8,
-                (*encoder.yuv_frame).linesize.as_ptr() as *const i32,
+                (*encoder.yuv_frame).linesize.as_ptr(),
             );
         }
         let format_us = t_format.elapsed().as_micros() as u64;

src/cap_portal.rs

@@ -139,6 +139,10 @@ pub struct CapPortal {
     frame_rx: Receiver<PwDmaBufFrame>,
     event_rx: Receiver<PwCtrlEvent>,
     pw_thread: Option<JoinHandle<()>>,
+    // Kept alive for CapPortal's whole lifetime: ashpd caches a zbus::Connection
+    // in a process-global OnceCell and hangs if the owning runtime drops first
+    // (see AGENTS.md). Never read after `new()`; only its Drop ordering matters.
+    #[allow(dead_code)]
     rt: Runtime,
     pw_dropped: Arc<AtomicU64>,
 }
@@ -154,7 +158,6 @@ struct PwThreadCtx {
     shutdown_read: OwnedFd,
     pw_fd: OwnedFd,
     node_id: u32,
-    fps: u32,
 }
 
 impl CapPortal {
@@ -209,7 +212,6 @@ impl CapPortal {
             shutdown_read: unsafe { OwnedFd::from_raw_fd(efd) },
             pw_fd,
             node_id,
-            fps: args.fps,
         };
 
         let pw_thread = thread::Builder::new()
@@ -697,7 +699,6 @@ fn pipewire_thread(ctx: PwThreadCtx) {
         shutdown_read,
         pw_fd,
         node_id,
-        fps: _,
     } = ctx;
 
     let mainloop = match pw::main_loop::MainLoopBox::new(None) {
@@ -1070,15 +1071,6 @@ fn pipewire_thread(ctx: PwThreadCtx) {
     // PipeWire global state is intentionally not deinitialized here — see pw::init() comment above.
 }
 
-/// 将四个 ASCII 字符编码为 32 位 FourCC (Four Character Code) 标识符
-///
-/// FourCC 是多媒体领域中广泛使用的像素格式标识方式。
-/// 编码规则: 第一个字符在最低 8 位，依次向高位排列。
-/// 例如: "BGRA" → 0x41524742 (小端序存储为 'B','G','R','A')
-const fn fourcc(a: u8, b: u8, c: u8, d: u8) -> u32 {
-    (a as u32) | ((b as u32) << 8) | ((c as u32) << 16) | ((d as u32) << 24)
-}
-
 /// 将 PipeWire SPA 视频格式转换为 DRM FourCC 格式
 ///
 /// PipeWire 使用自己的 VideoFormat 枚举，而 DRM/KMS 使用 FourCC 格式标识。

src/state.rs

@@ -77,8 +77,6 @@ pub trait CaptureSource: Sized + 'static {
 pub struct OutputInfo {
     pub name: String,
     pub transform: Transform,
-    pub physical_size: (i32, i32),
-    pub logical_position: (i32, i32),
 }
 
 #[derive(Default)]
@@ -174,7 +172,6 @@ pub(crate) enum EncConstructionStage<S: CaptureSource> {
         dmabuf: ZwpLinuxDmabufV1,
     },
     Streaming {
-        output_info: OutputInfo,
         output: WlOutput,
         enc: StreamingEncoder,
         cap: S,
@@ -209,7 +206,6 @@ pub enum InFlightSurface<S: CaptureSource> {
 pub struct State<S: CaptureSource> {
     pub(crate) stage: EncConstructionStage<S>,
     pub in_flight_surface: InFlightSurface<S>,
-    pub starting_timestamp: Option<i64>,
     pub stats_start_time: Option<Instant>,
     pub stats_last_time: Option<Instant>,
     pub stats_frames: u64,
@@ -302,7 +298,6 @@ impl<S: CaptureSource> State<S> {
                 wlr_head_proxy_to_name: HashMap::new(),
             },
             in_flight_surface: InFlightSurface::None,
-            starting_timestamp: None,
             stats_start_time: None,
             stats_last_time: None,
             stats_frames: 0,
@@ -479,7 +474,6 @@ impl<S: CaptureSource> State<S> {
     pub fn on_frame_allocd(&mut self, frame: S::Frame, format: u32, width: u32, height: u32) {
         let (frames_rgb_ctx, dmabuf, cap) = match &mut self.stage {
             EncConstructionStage::Streaming {
-                output_info: _,
                 output: _,
                 enc,
                 dmabuf,
@@ -829,7 +823,6 @@ impl<S: CaptureSource> State<S> {
             bitrate
         );
         self.stage = EncConstructionStage::Streaming {
-            output_info,
             output,
             enc,
             cap,
@@ -985,8 +978,6 @@ impl<S: CaptureSource> State<S> {
                 .or(info.wl_name.clone())
                 .unwrap_or_else(|| format!("output-{}", output_names[target_idx])),
             transform: info.transform.unwrap(),
-            physical_size: info.physical_size.unwrap(),
-            logical_position: info.logical_position.unwrap_or((0, 0)),
         };
         let output = bound_outputs[target_idx].clone();
 

src/state_portal.rs

@@ -2,6 +2,7 @@
 // AsRawFd is required by frame.fd.as_raw_fd() in build_drm_descriptor below
 // but rustc emits a false "unused_imports" warning because OwnedFd also has
 // an inherent as_raw_fd — same quirk as avhw.rs. E0599 if removed → keep it.
+#[allow(unused_imports)]
 use std::os::fd::AsRawFd;
 use std::path::PathBuf;
 use std::sync::atomic::{AtomicBool, Ordering};