docs: session handoff note for #135 stdlib AOT (next-Claude brief)

Standalone, dated handoff for whoever resumes #135: what landed (slices
1-8,11 + front, ~11/19 files compiling), what remains (slice 9 &mut,
slice 12 typecheck, io/math), and an explicit concurrency warning that
this clone was worked by two parallel sessions (open PRs #167/#170 are
the other session's). Points at the canonical triage doc + build setup.

Refs #128, #135.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: hyperpolymath

docs/history/SESSION-HANDOFF-2026-05-18.md

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+<!-- SPDX-License-Identifier: PMPL-1.0-or-later -->
+<!-- SPDX-FileCopyrightText: 2026 hyperpolymath -->
+
+# Session handoff — #135 stdlib AOT (note for the next Claude)
+
+**Date:** 2026-05-17 → 2026-05-18. **Read `docs/history/STDLIB-AOT-TRIAGE.md`
+first** — it is the authoritative live punch list.
+
+## What this work was
+
+Epic **#128 / #135**: make every `stdlib/*.affine` compile through
+`resolve → typecheck → codegen` (Deno-ESM). This was the estate's
+ReScript-port bottleneck.
+
+## What landed (merged to `main`, ~20 PRs, #149–#169)
+
+Front: #131 (`>>` keystone), #134 (unwrap soundness), #132 (ADR-011
+namespace), #133 (single-ownership dedup).
+
+#135 slices merged: **1** `fn(x)=>e` lambdas · **2** slice index
+`e[a:b]` · **3** bare `effect E;` + ADR-008 `-> T / E` · **4** `total`
+keyword-rename + `Iterator::collect` Vec→`[]` · **5** trait default
+bodies · **6/6b** `try`/`ref`/`as` keyword-as-ident renames · **7**
+let-polymorphism (generic fns were silently monomorphic — high-leverage
+typecheck fix) · **8** module visibility/imports · **11** resolver
+two-pass (forward refs + mutual recursion). Slice **10** (effects
+generic-extern kinds) landed via a parallel session.
+
+Result: **~11/19 stdlib files compile end-to-end** (prelude, string,
+effects, Core + 7 module files). The two hardest *enabling* fixes
+(sl.7 let-poly, sl.11 resolver two-pass) are done — nothing is blocked
+on the resolver or the typecheck wall any more.
+
+## What remains (see triage doc for precise per-file root causes)
+
+- **slice 9** — `option` `&mut Option<T>` ref params (`take`/
+  `get_or_insert`); affine/borrow lowering, ownership-soundness-critical.
+- **slice 12** — deeper typecheck on `result`/`collections`/`testing`/
+  `traits` (now past resolution).
+- **io / math** — cross-module `split` (in `string.affine`) / `trunc`;
+  see open PRs below.
+
+## ⚠️ Concurrency note (important)
+
+This repo was worked by **two Claude sessions in parallel** in the same
+clone, under the shared `hyperpolymath` git identity. Open PRs **#167**
+(slice 10 `Ref<T>` kind) and **#170** (`trunc` builtin) belong to the
+*other* session — do not assume they are yours. Before resuming:
+re-verify `origin/main`, base any branch on it (never on a stray
+checked-out branch), and coordinate on `io`/`math`/resolver/`string`
+which the other session was actively editing. Mechanics + hazards are
+in memory `affinescript-spine-rederived`, `split-merge-failure-mode`,
+`stray-branch-base-misdetection`, `git-checkout-discards-uncommitted-edits`.
+
+## Build
+
+Canonical clone is `/home/hyperpolymath/dev/affinescript` (has the
+`_opam` local switch; the `repos/affinescript` clone has no toolchain).
+Prefix every command:
+
+```
+export PATH="/usr/bin:$PATH"
+eval $(opam env --switch=/home/hyperpolymath/dev/affinescript --set-switch)
+dune build && dune test     # full suite was green at 233 tests
+```
+
+Discipline that paid off this session: isolate genuine root causes with
+minimal repros before changing the compiler; commit a green change
+*before* any conflict-check/file-swap; for grammar edits, diff menhir
+conflict counts before/after; one scoped slice per PR; rigorous triage
+over a damaging partial pass.