benchd M5a: the pty core — daemon-owned sessions, raw attach

daemon/AGENTS.md

@@ -19,8 +19,10 @@ knows nor needs the Rust toolchain, in either direction.
 
 - `crates/bench-wire` — every wire type and shared resolution rule, spelled once. If
   `benchd` and `bench` could disagree about a value, its rule belongs here.
-- `crates/benchd` — the daemon. Foreground, one unix socket, serial request handling.
-- `crates/bench` — the CLI, the one agent-facing surface (and the future skill surface).
+- `crates/bench-session` — the pty core: agent allowlist, postures/model/effort/resume
+  argv (one spelling, unit-tested), the ring, the attach relay, drain-then-die close.
+- `crates/benchd` — the daemon. Foreground, one unix socket, a thread per connection.
+- `crates/bench` — the CLI, the one agent-facing surface, and the attach client.
 - There is deliberately **no root `Cargo.toml`** in the repo: `cargo` at the repo root
   fails loudly instead of half-working.
 

daemon/Cargo.toml

@@ -2,7 +2,7 @@
 # `cargo` at the repo root should fail loudly, not half-work (bench-roadmap.md, M0).
 [workspace]
 resolver = "2"
-members = ["crates/bench-wire", "crates/benchd", "crates/bench"]
+members = ["crates/bench-wire", "crates/bench-session", "crates/benchd", "crates/bench"]
 
 [workspace.package]
 version = "0.0.1"

daemon/crates/bench-session/Cargo.toml

@@ -0,0 +1,8 @@
+[package]
+name = "bench-session"
+version.workspace = true
+edition.workspace = true
+description = "The pty core: daemon-owned sessions hosting full interactive agent TUIs."
+
+[dependencies]
+portable-pty = "0.9"