docs(selfhost): AST parity 286→339/579 (async/resource stmts + typed-let fix)

Ledger SH-025 + memory + plan refreshed for the async/resource construct sweep
(manage/spawn/await, with/task_group/select) and the type-annotated-let value-split
fix. AST structure parity now 339/579, 0 run-failures.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Author: olwang

docs/ledgers/rss-selfhost-ledger.md

@@ -868,7 +868,7 @@ gap is VM value-representation / intrinsic-dispatch cost (the next big lever).
   across all backends; RS0037 removed as a restriction and repurposed for arity;
   spec §20.1 amended.
 
-### SH-025 — AST-dump parity: streaming rss producer at 286/576, residual grammar is the growing tail
+### SH-025 — AST-dump parity: streaming rss producer at 339/579, residual grammar is the growing tail
 
 - **Context:** step 2 of frontend object parity (after the AST-dump format +
   oracle keystone, SH-adjacent). `selfhost/astdump.rss` is a recursive-descent
@@ -900,10 +900,15 @@ gap is VM value-representation / intrinsic-dispatch cost (the next big lever).
   rest), **interpolated strings** (`$"…{e}…"` → String.format desugar, embedded
   exprs re-tokenized), and **statement_end line-continuation** (`;` terminator,
   `.`/`?` postfix, `| & + * / % ^` operator wrapping, generic-angle depth).
+  Also (async/resource sweep): **`manage`/`spawn`/`await` prefix exprs**,
+  **`with … as …`/`task_group`/`select` statements**, and a **type-annotated-let
+  fix** (`let x: Option<Int> = …` — the value split is the first `=`, not
+  top_assign whose `>=` guard skipped the `=` after a generic `>`).
 - **Milestones (each a commit + ratcheted floor):** base fns 58 → decls 121 →
   match 178 → generic calls 225 → closures 239 → for+literals 242 → unary/negative
-  245 → **effect-receiver 248 → no-effect-receiver+attrs+effects+body 273 →
-  explicit-fn+tuple/list-patterns 279 → interpolation 280 → line-continuation 286**.
+  245 → effect-receiver 248 → no-effect-receiver+attrs+effects+body 273 →
+  explicit-fn+tuple/list-patterns 279 → interpolation 280 → line-continuation 286 →
+  **manage/spawn/await+with/task-group/select 331 → typed-let fix 339**.
 - **Residual (the tail):** **protocols/impls/native-modules** — DEFERRED: needs a
   two-pass driver (items in source order, then protocol/impl decl sections) plus an
   `emit_function` refactor to reproduce the synthetic method transforms (inject

docs/self-hosting-stress-test-plan.md

@@ -285,7 +285,7 @@ materialized). Parity harness: `ast_parity_tiny_sample` + `ast_parity_samples`
 count still clears the floor). That corpus gate runs the reg-VM over ~570 files and
 is slow in a debug build — run it in `--release` for a quick measurement (~100s);
 the fast non-ignored inner-loop gate is `ast_parity_samples`. Current reach:
-**286/576 byte-exact (AST structure), 0 run-failures** (the producer never crashes; unsupported
+**339/579 byte-exact (AST structure), 0 run-failures** (the producer never crashes; unsupported
 constructs mismatch rather than panic), roughly doubled this session via ratcheted
 milestones: base fns 58 → declarations 121 → match 178 → generic calls 225 →
 closures 239 → for/literals 242 → unary/negative 245. Covered: fns (generics/