feat(evaluator): PR-E Bind callable entry

[briansrls]

Summary

Implements the PR-E Bind/callable-entry evaluator prerequisite inside the existing Rust evaluator surface.

• wires Behavior::Bind through eval_node
• adds eval_bind for bounded body-entry evaluation through BindNode.value
• copies declared BindNode.params from caller-visible frames into a fresh callable frame before evaluating the body port
• preserves stack balance on success and diagnostic paths
• keeps scope out of E6 lens fold, runner work, substrate changes, and new runtime carriers

Validation

• cargo fmt --all --check
• RUST_MIN_STACK=33554432 RUSTC_WRAPPER= cargo test -p v3-compiler --lib evaluator::tests
• RUST_MIN_STACK=33554432 RUSTC_WRAPPER= cargo clippy -p v3-compiler --lib -- -D warnings
• RUST_MIN_STACK=33554432 RUSTC_WRAPPER= cargo test -p v3-compiler --lib

Note: this checkout's inline v3-compiler lib test binary overflows the default Rust test thread stack even on unchanged evaluator frame-helper tests, so the local lib/evaluator test runs used RUST_MIN_STACK=33554432.

[briansrls]

Manager pass: this is the right Bind/callable-entry prerequisite shape. It wires only Behavior::Bind, evaluates through the existing eval_port/eval_node surface, copies declared params from the caller-visible frames into a fresh callable frame, and restores stack depth on success, duplicate-param failure, unbound-param failure, and body diagnostics.

Scope looks clean: no E6 fold driver, no runner work, no substrate/value/report shape changes. Hold for CI/reviews, but I do not see a manager-blocking issue from this pass.

— sent from snappy-moth-795

[briansrls]

Review metadata

• Provider / model: cursor / composer-2
• Commit: aff92b01 · Trigger: schedule
• Comparison: origin/main @ 331b9ebe ... review/pr-1496-aff92b01 @ aff92b01
• Thinking: 48s wall

---

Findings: None. The diff implements Bind with explicit dispatch (no open behavior => fallback), keeps failures on typed EvalError / EvalFrameError paths, resolves parameter bindings before pushing the inner frame so unbound parameters never allocate a frame, and always pop_frames after the body so the stack is restored on both success and failure. Tests use minimal Dag construction and assert observable outcomes (value, frame depth, caller binding preservation, duplicate/unbound errors, body diagnostics), consistent with TESTING.md for this kind of unit.

Verdict: APPROVE — Scoped evaluator change: removes the UnsupportedBehavior stub for Bind, adds the documented callable-frame behavior, and replaces it with targeted regression tests. No concrete conflict with INVARIANTS.md, docs/modeling-discipline.md, CODING.md, or TESTING.md visible in the diff.

[briansrls]

Review metadata

• Provider / model: codex / unknown
• Commit: aff92b01 · Trigger: schedule
• Thinking: 137s wall

---

Non-blocking — Strengths

• src/v3/compiler/src/lib.rs Code-only evaluator slice: Bind now covers the remaining L1 behavior, keeps failures typed through EvalError/EvalFrameError, and tests stack restoration on success and diagnostics.

✅ No blocking concerns for this Bind callable-entry implementation.

[briansrls]

Review metadata

• Provider / model: codex / codex-default
• Commit: 57f1a584 · Trigger: schedule
• Comparison: origin/main @ 11c12d08 ... review/pr-1496-57f1a584 @ 57f1a584
• Thinking: 60s wall

---

Verdict: APPROVE

Diff is narrowly scoped to making Behavior::Bind executable in the evaluator, with typed failure paths for missing/duplicate frame bindings and stack restoration tests around diagnostics. I did not see concrete violations of the pinned invariants, modeling discipline, coding guidance, or testing guidance. Builds/tests were not run per instruction.