iter form-a.tidy: form_a.md class/instance/constraints + 3 documentary drift items

Six-task post-fieldtest documentary tidy. No production-code behaviour
changes; 559 tests green at every per-task gate.

T1-T3: form_a.md additions
- §Definitions intro "Three kinds" -> "Five kinds".
- New `### Class — (class ...)` subsection: EBNF carries optional
  superclass (0 or 1 per ClassDef.superclass schema), method
  signatures with optional defaults; anchored to
  examples/test_22c_user_class_e2e.ail (ok 24/2).
- New `### Instance — (instance ...)` subsection: EBNF carries the
  (method NAME (body LAM-TERM))* shape; canonical-form CLASS-REF
  rule explicitly stated (bare same-module / qualified cross-module);
  two examples — same-module abbreviated from
  mq3_class_eq_vs_fn_eq_classmod.ail and cross-module qualified
  from show_user_adt.ail; bare-cross-module-class-ref diagnostic
  named inline.
- §Types `(forall ...)` line extended with optional `(constraints
  (constraint CLASS-REF TYPE)+)?` clause; explanatory paragraph
  added with no-instance diagnostic anchor; fifth example added
  to the Examples block anchored to cmp_max_smoke.ail.

T4: docs/specs/2026-05-13-form-a-default-authoring.md "seven
carve-outs" → "eight carve-outs" at 6 sites contradicting the
§C4(b) compile-time-embed amendment (commit 9fcda8b). Sites:
preamble line 11, §C1 line 170, §C2 line 191, §C3 line 218,
§"Data flow" lines 363 + 374. Post-edit grep returns 4 surviving
"seven" lines (233, 238, 463, 469), all correctly §C4(a)-scope
or arithmetic/future-state.

T5: crates/ailang-core/src/hash.rs:50-57 — delete empty
`#[cfg(test)] mod tests {}` placeholder + 6-line relocation
comment. Tests live in crates/ailang-core/tests/hash_pin.rs
since form-a.1 T5; placeholder served no purpose. hash_pin.rs
still 10/10 passing.

T6: crates/ailang-surface/tests/round_trip.rs — module-level
`//!` and inner `///` docstrings rewritten to the post-T10
four-property framing (parse-determinism / idempotency /
CLI-pipeline-idempotency / carve-out-anchor) instead of the
retired Direction-1/Direction-2 language. Sibling-crate
breadcrumbs added pointing at the other two enforcement points
(roundtrip_cli.rs, carve_out_inventory.rs).

Drift item B2 (audit-form-a "plan file two sites") dropped per
recon verification: docs/plans/2026-05-13-iter-form-a.1.md
contains zero defective "seven" sites; all four hits are
internally scoped to §C4(a), arithmetic, or future-state.
Decision recorded in the journal.

Closes 2 of 3 fieldtest-form-a spec_gap findings (#2 form_a.md
typeclass surface + #3 form_a.md class-qualifier rule for
instance) and 3 of 4 audit-form-a drift items.

docs/journals/2026-05-13-iter-form-a.tidy.md

@@ -0,0 +1,103 @@
+# iter form-a.tidy — close 3 of 4 documentary drift items from audit-form-a + fix 5 contradictory "seven carve-outs" sites
+
+**Date:** 2026-05-13
+**Started from:** 5e94204c218c410d44fbb8e658b677a7294744b0
+**Status:** DONE
+**Tasks completed:** 6 of 6
+
+## Summary
+
+Pure documentary tidy iteration. Three new sections landed in
+`crates/ailang-core/specs/form_a.md` (Class declarations, Instance
+declarations, Constraints on polymorphic fns), each anchored to a
+real corpus fixture (`test_22c_user_class_e2e.ail`,
+`mq3_class_eq_vs_fn_eq_classmod.ail`, `show_user_adt.ail`,
+`cmp_max_smoke.ail`) and each fixture was `ail check`-verified to
+produce the expected symbol counts before close. Six sites in
+`docs/specs/2026-05-13-form-a-default-authoring.md` had "seven
+carve-outs" tightened to "eight carve-outs" to match the §C4(b)
+amendment. The empty `#[cfg(test)] mod tests {}` placeholder plus
+its 6-line relocation comment was deleted from
+`crates/ailang-core/src/hash.rs` (tests live in
+`crates/ailang-core/tests/hash_pin.rs` since form-a.1 T5). The
+`round_trip.rs` module-level and inner docstrings were rewritten
+to use the post-T10 four-property framing (parse-determinism /
+idempotency-under-print / CLI-pipeline-idempotency /
+carve-out-anchor) instead of the retired Direction-1/Direction-2
+language, with cross-references to the sibling enforcement points
+in `crates/ail/tests/roundtrip_cli.rs` and
+`crates/ailang-core/tests/carve_out_inventory.rs`.
+
+No production-code behaviour changed. Workspace test count holds
+at 559 passed at every per-task gate.
+
+## Per-task notes
+
+- iter form-a.tidy.1: `form_a.md` Class declarations section landed; §Definitions
+  intro updated `Three kinds` → `Five kinds`; example anchored to
+  `examples/test_22c_user_class_e2e.ail` (`ok (24 symbols across 2 modules)`).
+- iter form-a.tidy.2: `form_a.md` Instance declarations section landed; two
+  examples (same-module abbreviated from `mq3_class_eq_vs_fn_eq_classmod.ail`,
+  cross-module from `show_user_adt.ail`); `bare-cross-module-class-ref`
+  diagnostic anchor named inline.
+- iter form-a.tidy.3: `form_a.md` Constraints on polymorphic fns: extended
+  the four-shapes EBNF `(forall ...)` line with optional `(constraints ...)`
+  clause, added explanatory paragraph (with `no-instance` diagnostic anchor),
+  added fifth example to the Examples block anchored to `cmp_max_smoke.ail`.
+- iter form-a.tidy.4: `docs/specs/2026-05-13-form-a-default-authoring.md`
+  six "seven" → "eight" edits across the preamble + §C1 + §C2 + §C3 + §"Data flow"
+  (two sites). Post-edit grep returned 4 surviving "seven" mentions at lines
+  233, 238, 463, 469 — all correctly §C4(a)-scoped or arithmetic/future-state
+  (see Concerns below for one carrier-vs-plan transcription drift).
+- iter form-a.tidy.5: `hash.rs` empty `mod tests {}` placeholder + 6-line
+  relocation comment block deleted (9 lines including the preceding blank).
+  `hash_pin.rs` integration tests still 10/10 passing.
+- iter form-a.tidy.6: `round_trip.rs` module-level `//!` and inner `///`
+  rewritten to four-property framing with sibling-crate breadcrumbs.
+  `grep -n 'Direction [12]'` now zero hits.
+
+## Concerns
+
+- T4 carrier-vs-plan transcription drift on the Step 6 sanity-grep expected
+  output. The plan's Step 6 expected-output block listed four lines (233,
+  238, 463, 469) but the carrier compressed this to "exactly the three
+  surviving lines named in T4 Step 6 (lines 238, 463, 469)". The actual
+  post-edit grep returns four lines matching the plan listing; line 233
+  is §C4(a)-scope ("(seven files; the canonical") and is correctly retained.
+  No edit was missed. The carrier's three-line restatement was wrong;
+  the plan's four-line listing was right. Recording so a future auditor
+  re-reading the carrier doesn't second-guess the result.
+
+## Known debt
+
+- (none)
+
+## Files touched
+
+- `crates/ailang-core/specs/form_a.md` (+105/-)
+- `crates/ailang-core/src/hash.rs` (-9)
+- `crates/ailang-surface/tests/round_trip.rs` (+19/-12)
+- `docs/specs/2026-05-13-form-a-default-authoring.md` (six 1-line edits)
+
+## Phase 3 (E2E coverage)
+
+Deliberately skipped per carrier: pure-documentary iter, no
+behaviour change to cover. Verification gate was the per-task
+`cargo test --workspace` smoke (559 green at every task close)
+plus the per-task `ail check` runs on the four corpus fixtures
+cited in the new form_a.md sections, all producing the expected
+symbol counts (`test_22c_user_class_e2e.ail` ok 24/2,
+`mq3_class_eq_vs_fn_eq_classmod.ail` ok 22/2,
+`show_user_adt.ail` ok 23/2, `cmp_max_smoke.ail` ok 22/2).
+
+## Decision recorded — Drift item B2 (plan-file "seven carve-outs" orphans)
+
+Per plan §"Decision recorded" and the recon report: `docs/plans/2026-05-13-iter-form-a.1.md`
+contains zero defective `seven` mentions; its four hits are all internally
+scoped to §C4(a) (which IS seven), arithmetic, or future-state. The
+audit-form-a journal's "two sites" claim against the plan file did not
+match its contents at HEAD. No plan-file edit included in this iter.
+
+## Stats
+
+bench/orchestrator-stats/2026-05-13-iter-form-a.tidy.json

docs/specs/2026-05-13-form-a-default-authoring.md

@@ -8,7 +8,7 @@
 
 Make Form A (`.ail`) the sole authoring surface for every program in
 the working tree. After this milestone, the only `.ail.json` files
-that remain in the repository are seven specific negative-test
+that remain in the repository are eight specific negative-test
 fixtures whose subject matter cannot be expressed in Form A by
 construction. Every other `.ail.json` is rendered to its `.ail`
 sibling via `ail render`, and the now-redundant `.ail.json` is
@@ -167,7 +167,7 @@ not the projection's relation to the AST.
 ### C1. Migration script
 
 A one-shot Bash script `scripts/migrate-to-form-a.sh` (new file)
-walks `examples/*.ail.json`, skips the seven carve-outs (named
+walks `examples/*.ail.json`, skips the eight carve-outs (named
 explicitly in the script body), invokes `ail render` to produce
 the sibling `.ail`, and `rm`s the JSON counterpart. The script is
 idempotent (re-running on a partially migrated tree is a no-op for
@@ -188,7 +188,7 @@ The refactor is mechanical but spans three classes of consumer:
    `examples/<stem>.ail.json` with `fs::read_to_string` and
    passes the bytes to `Module::from_json` or the workspace
    loader. The refactor reads `examples/<stem>.ail` and parses via
-   `ailang_surface::parse_module_from_str`. The seven carve-outs
+   `ailang_surface::parse_module_from_str`. The eight carve-outs
    continue to use the `.ail.json` path (they have no `.ail` form
    by construction).
 3. **Bench drivers** (`bench/*.py`, `bench/run.sh`). The drivers
@@ -215,7 +215,7 @@ so the invariant restates as:
   | ail parse` (one round) is byte-identical to direct
   `ail parse` of the source `.ail`. Pins the user-facing CLI
   against drift internal tests cannot see.
-- **Carve-out anchor.** The seven `.ail.json`-only fixtures are
+- **Carve-out anchor.** The eight `.ail.json`-only fixtures are
   negative-tests (load-time / typecheck-time rejection); they
   participate only in the existing rejection-shape tests, not in
   the roundtrip gate. Their presence is the *only* surviving
@@ -360,7 +360,7 @@ author writes:          examples/<name>.ail             (every program)
                               v
                    Module value -> typecheck, codegen, ...
 
-except for the seven carve-outs:
+except for the eight carve-outs:
                         examples/<carve-out>.ail.json
                               |
                               v
@@ -371,7 +371,7 @@ Cross-module imports continue to use module names, not file paths;
 the workspace loader walks `examples/*` and accepts either extension
 for any module it loads. Since the bulk of the corpus is single-
 extension post-migration, the loader's extension-dispatch is exercised
-only by the seven carve-outs (and by any test that explicitly mixes
+only by the eight carve-outs (and by any test that explicitly mixes
 the two forms for migration testing).
 
 ## Error handling