fix: Unit 1 — publishing blocker + convention fixes (R-01, R-02, R-03)

- R-01: remove `readme = "README.md"` from Cargo.toml (no README yet;
  the field will be restored when the README is written as the
  second-to-last step before publishing). `cargo publish --dry-run
  --allow-dirty` now succeeds.
- R-02: replace the three `expect` calls in non-test library code per
  AGENTS.md §2:
  - `channels/operations.rs` `register_openable`: collapse the
    `is_none()` early-return + `expect("checked above")` into a
    single `ok_or_else(...)?` (same error message, no expect).
  - `core/types.rs` `StreamBidiStreamSource::accept_bi` and
    `close`: use `unwrap_or_else(|e| e.into_inner())` for the
    poisoned `std::sync::Mutex` (per the convention, a panic in one
    operation must not cascade).
- R-03: remove the unnecessary `#[allow(dead_code)]` from
  `registry::context::generate_request_id` — it is called from
  `registry::env`, `protocol::connection` (3 sites), and tests.

The review's R-02 acceptance-gate grep is line-level
(`grep -v 'mod tests'` filters by line, not scope), so the ~269
`.expect(` calls inside `#[cfg(test)] mod tests` blocks still match
it. The intent of R-02 — no `expect` in library (non-test) code — is
met: the three non-test sites identified in the review are removed, and
a targeted grep for the removed strings returns no matches.

Verification:
  cargo test                                    → 483 passed, 0 failed
  cargo clippy --all-targets -- -D warnings     → clean
  cargo fmt --check                             → clean
  cargo doc --no-deps                           → clean (0 warnings)
  cargo publish --dry-run --allow-dirty         → succeeds

Cargo.toml

@@ -6,7 +6,6 @@ rust-version = "1.85"
 license = "MIT OR Apache-2.0"
 description = "Call + channels RPC: structured JSON operations, streaming subscriptions, service discovery, and N-channel multiplexing over one transport stream"
 repository = "https://git.alk.dev/alkdev/alkcall"
-readme = "README.md"
 keywords = ["rpc", "json-rpc", "multiplexing", "wire-format", "alpn"]
 categories = ["network-programming", "asynchronous", "encoding"]
 exclude = [".opencode/", "docs/reviews/", "docs/research/", "docs/sdd_process.md", "Cargo.lock"]

src/channels/operations.rs

@@ -405,14 +405,17 @@ impl ChannelCore {
     ) -> Result<(), String> {
         let op_type = spec.op_type;
         let channel_open = spec.channel_open.clone();
-        if channel_open.is_none() {
-            return Err(format!(
+        let alpn = channel_open
+            .as_ref()
+            .ok_or_else(|| {
+                format!(
                     "register_openable: spec `{}` has no channel_open marker — \
                      use `OperationSpec::with_channel_open` to set it (ADR-047 §2)",
                     spec.name
-            ));
-        }
-        let alpn = channel_open.expect("checked above").alpn.to_string();
+                )
+            })?
+            .alpn
+            .to_string();
 
         let manager = self.manager.clone();
         let policy = Arc::clone(&self.policy);

src/core/types.rs

@@ -433,7 +433,7 @@ struct StreamBidiStreamSource {
 #[async_trait]
 impl BidiStreamSource for StreamBidiStreamSource {
     async fn accept_bi(&self) -> Result<BiStream, StreamError> {
-        let mut guard = self.stream.lock().expect("stream mutex poisoned");
+        let mut guard = self.stream.lock().unwrap_or_else(|e| e.into_inner());
         match guard.take() {
             Some(stream) => Ok(stream),
             None => Err(StreamError::ConnectionClosed),
@@ -453,7 +453,7 @@ impl BidiStreamSource for StreamBidiStreamSource {
     /// §"Negative"). The `_` prefix is intentional — the signature matches
     /// the public `Connection::close` API (ADR-070 §"REQ-CORE-02").
     fn close(&self, _code: u32, _reason: &str) {
-        let _ = self.stream.lock().expect("stream mutex poisoned").take();
+        let _ = self.stream.lock().unwrap_or_else(|e| e.into_inner()).take();
     }
 }
 

src/registry/context.rs

@@ -144,7 +144,6 @@ impl Default for ScopedPeerEnv {
     }
 }
 
-#[allow(dead_code)]
 pub(crate) fn generate_request_id() -> String {
     uuid::Uuid::new_v4().to_string()
 }