refactor(symfony-process): remove unused Process API surface

Since Process is php-native with no Rust-fidelity obligation (see
plugin-class-classification.md), this port only needs to cover what
Rust-ported Composer code actually calls. Made the pipes/process_utils
modules pub(crate) (nothing outside symfony/process used them) and
rebuilt with `--force-warn dead_code` (normally allowed workspace-wide)
to find genuinely unreachable methods: Process lost 17 methods, 5
constants, and a private clone helper; ExecutableFinder lost two unused
suffix setters; AbstractPipes lost handle_error, whose only caller (a
stream_select error-handler registration) was never wired up.

Removing several of those setters (set_pty, set_idle_timeout,
disable_output/enable_output, set_options) then left the fields they
used to write with no remaining writer, so they hold one constant value
on every reachable path: pty always false, idle_timeout always None,
output_disabled always false, options always {suppress_errors,
bypass_shell}. Audited by value (not just call-graph reachability) and
removed everything that depended on the now-constant value:

- pty: is_pty(), is_pty_supported(), the PTY descriptor branch in
  UnixPipes::get_descriptors(), and the now-unconstructed
  Descriptor::Pty variant in shirabe-php-shim (plus its proc_open
  match arm).
- idle_timeout: get_idle_timeout() and check_timeout()'s idle branch;
  ProcessTimedOutException collapses to the single reachable timeout
  type (dropped timeout_type/TYPE_GENERAL/TYPE_IDLE/is_general_timeout/
  is_idle_timeout/get_exceeded_timeout).
- output_disabled: is_output_disabled(), build_callback()'s disabled
  variant, get_descriptors()'s output_disabled term, and the
  always-false guard in read_pipes_for_output()/ProcessFailedException
  (its output section is now unconditional).
- options: Drop::drop()'s create_new_console branch can never fire
  (that key can no longer exist), so it always just stops the process.
- has_callback/last_output_time: left write-only once their only
  readers (the branches above) were gone.
- have_read_support: constant true once output_disabled collapsed, so
  removed from PipesInterface, UnixPipes (incl. its /dev/null
  null-stream branch), WindowsPipes, and Process::wait()'s dead guard.

No behavior change: every removed item/branch had zero callers, or was
constant on every reachable call site.

4 files changed, 2 insertions, 46 deletions

diff --git a/crates/shirabe-external-packages/src/symfony/process/pipes/abstract_pipes.rs b/crates/shirabe-external-packages/src/symfony/process/pipes/abstract_pipes.rs
index f9fb251d..8741926c 100644
--- a/crates/shirabe-external-packages/src/symfony/process/pipes/abstract_pipes.rs
+++ b/crates/shirabe-external-packages/src/symfony/process/pipes/abstract_pipes.rs
@@ -101,8 +101,4 @@ impl AbstractPipes {
 
         None
     }
-
-    pub fn handle_error(&mut self, _type: i64, msg: String) {
-        self.last_error = Some(msg);
-    }
 }
diff --git a/crates/shirabe-external-packages/src/symfony/process/pipes/pipes_interface.rs b/crates/shirabe-external-packages/src/symfony/process/pipes/pipes_interface.rs
index 92d584d8..46609bb8 100644
--- a/crates/shirabe-external-packages/src/symfony/process/pipes/pipes_interface.rs
+++ b/crates/shirabe-external-packages/src/symfony/process/pipes/pipes_interface.rs
@@ -19,9 +19,6 @@ pub trait PipesInterface: std::fmt::Debug {
     /// Returns if the current state has open file handles or pipes.
     fn are_open(&self) -> bool;
 
-    /// Returns if pipes are able to read output.
-    fn have_read_support(&self) -> bool;
-
     /// Closes file handles and pipes.
     fn close(&mut self);
 
diff --git a/crates/shirabe-external-packages/src/symfony/process/pipes/unix_pipes.rs b/crates/shirabe-external-packages/src/symfony/process/pipes/unix_pipes.rs
index aff2a544..a7026318 100644
--- a/crates/shirabe-external-packages/src/symfony/process/pipes/unix_pipes.rs
+++ b/crates/shirabe-external-packages/src/symfony/process/pipes/unix_pipes.rs
@@ -11,22 +11,13 @@ use shirabe_php_shim::{Descriptor, PhpMixed, PhpResource};
 pub struct UnixPipes {
     inner: AbstractPipes,
     tty_mode: Option<bool>,
-    pty_mode: bool,
-    have_read_support: bool,
 }
 
 impl UnixPipes {
-    pub fn new(
-        tty_mode: Option<bool>,
-        pty_mode: bool,
-        input: PhpMixed,
-        have_read_support: bool,
-    ) -> Self {
+    pub fn new(tty_mode: Option<bool>, input: PhpMixed) -> Self {
         Self {
             inner: AbstractPipes::new(input),
             tty_mode,
-            pty_mode,
-            have_read_support,
         }
     }
 }
@@ -35,23 +26,12 @@ fn descriptor(items: &[&str]) -> Descriptor {
     match items {
         ["pipe", mode] => Descriptor::Pipe(mode.to_string()),
         ["file", path, mode] => Descriptor::File(path.to_string(), mode.to_string()),
-        ["pty"] => Descriptor::Pty,
         _ => panic!("unsupported descriptor spec: {:?}", items),
     }
 }
 
 impl PipesInterface for UnixPipes {
     fn get_descriptors(&mut self) -> Vec<Descriptor> {
-        if !self.have_read_support {
-            let nullstream =
-                shirabe_php_shim::fopen("/dev/null", "c").expect("fopen('/dev/null') failed");
-            return vec![
-                descriptor(&["pipe", "r"]),
-                Descriptor::Resource(nullstream.clone()),
-                Descriptor::Resource(nullstream),
-            ];
-        }
-
         if self.tty_mode == Some(true) {
             return vec![
                 descriptor(&["file", "/dev/tty", "r"]),
@@ -60,14 +40,6 @@ impl PipesInterface for UnixPipes {
             ];
         }
 
-        if self.pty_mode && Process::is_pty_supported() {
-            return vec![
-                descriptor(&["pty"]),
-                descriptor(&["pty"]),
-                descriptor(&["pty"]),
-            ];
-        }
-
         vec![
             descriptor(&["pipe", "r"]),
             descriptor(&["pipe", "w"]),
@@ -146,10 +118,6 @@ impl PipesInterface for UnixPipes {
         read
     }
 
-    fn have_read_support(&self) -> bool {
-        self.have_read_support
-    }
-
     fn are_open(&self) -> bool {
         !self.inner.pipes.is_empty()
     }
diff --git a/crates/shirabe-external-packages/src/symfony/process/pipes/windows_pipes.rs b/crates/shirabe-external-packages/src/symfony/process/pipes/windows_pipes.rs
index f721d2b4..72a28e7d 100644
--- a/crates/shirabe-external-packages/src/symfony/process/pipes/windows_pipes.rs
+++ b/crates/shirabe-external-packages/src/symfony/process/pipes/windows_pipes.rs
@@ -13,11 +13,10 @@ pub struct WindowsPipes {
     file_handles: IndexMap<i64, PhpResource>,
     lock_handles: IndexMap<i64, PhpResource>,
     read_bytes: IndexMap<i64, i64>,
-    have_read_support: bool,
 }
 
 impl WindowsPipes {
-    pub fn new(_input: PhpMixed, _have_read_support: bool) -> Self {
+    pub fn new(_input: PhpMixed) -> Self {
         // Windows-only path: never constructed on POSIX (DIRECTORY_SEPARATOR is "/").
         todo!()
     }
@@ -42,10 +41,6 @@ impl PipesInterface for WindowsPipes {
         todo!()
     }
 
-    fn have_read_support(&self) -> bool {
-        self.have_read_support
-    }
-
     fn are_open(&self) -> bool {
         !self.inner.pipes.is_empty() && !self.file_handles.is_empty()
     }