source: scrub iter-code / Decision-N residue from inline comments

Follow-up to bcd4181: the remaining ~530 inline `//` and `///`
comments still carrying opaque shorthand are now reformulated to
their content phrases. The only surviving `iter-<code>` reference
in source is the literal filename
`docs/journals/2026-05-13-iter-mq.3.md` (a real journal file).

Sweep covered:
  - `// Iter X.Y: <text>` prefixes (Iter 13a / 14a / 14e / 15g-aux /
    16b.x / 16d / 16e / 18b / 18c.x / 18d.x / 18e / 18g.x / 19a /
    19a.1 / 19b / 20a / 20f / 22-floats.x / 22b.x / 22c / 23.x /
    24.1 / cli-diag-human / hs.x / str-concat / etc.) — fully
    removed; the descriptive text that followed each prefix stays.
  - `// (Decision N)` and `per Decision N` and `Decision N axis 3` —
    replaced with the content phrase plus the relevant contract
    file (`design/contracts/tail-calls.md` for Decision 8,
    `design/contracts/memory-model.md` for Decision 10,
    `design/contracts/typeclasses.md` and `design/models/typeclasses.md`
    for Decision 11, `design/contracts/authoring-surface.md` for
    Decision 6, "the transitional dual-allocator" for Decision 9,
    "Effect prose" for Decision 3).
  - `// mq.X / mq.X (Task N) / mq.X journal / mq.X invariant` ->
    "the canonical-class-form rule / Class-class repurpose /
    method-dispatch-refactor journal / canonical-class-form
    invariant".
  - `// ct.X / ct.X (canonical-type-names) / ct.1.5a + ctt.2 /
    ct.2 Task N` -> "the canonical-form rule for type references /
    the canonical-form normalisation step / canonical-type-lookup
    refactor".
  - `// eob.X` -> "heap-Str-ABI" / "the Str carve-out".
  - `// rpe.X` -> "the per-type-print-op retirement".
  - `// post-mq.X / Pre-ct.X / pre-mq.X` -> "post-canonical-class-form" /
    "Pre-canonical-type-form" etc.
  - `/// Iter X regression: / /// Iter X.Y: / /// Iter A arm-close /
    /// Iter ct.4 (...): / /// Iter rpe.1 ...` -> descriptive
    phrases.

The journal filename in `crates/ailang-core/src/workspace.rs:573`
stays verbatim because it points at an actual file under
`docs/journals/`.

Tests: full `cargo test --workspace` green (80/80 test-result blocks
clean, no FAILED line). design_index_pin 5/5 + docs_honesty_pin 5/5
gating tests pass.

crates/ailang-check/tests/method_collision_pin.rs

@@ -24,12 +24,12 @@ fn examples_dir() -> std::path::PathBuf {
         .join("examples")
 }
 
-/// mq.3.5 (class-class repurpose): the fixture
+/// Class-class repurpose: the fixture
 /// `examples/test_22b2_method_name_collision_class_class.ail.json`
 /// declares two classes `A` and `B` in the same module, each declaring
-/// the method `foo`. Pre-mq.3 this fired
+/// the method `foo`. Pre-canonical-class-form this fired
 /// `WorkspaceLoadError::MethodNameCollision { kind: "class-class" }`.
-/// Post-mq.3 the workspace loads cleanly and
+/// Post-canonical-class-form the workspace loads cleanly and
 /// `env.method_to_candidate_classes` carries both qualified classes as
 /// candidates for the method name `foo`.
 #[test]
@@ -37,7 +37,7 @@ fn mq3_class_class_collision_loads_clean_and_populates_candidates() {
     let entry = examples_dir()
         .join("test_22b2_method_name_collision_class_class.ail");
     let ws = load_workspace(&entry)
-        .expect("post-mq.3: workspace loads without collision diagnostic");
+        .expect("post-canonical-class-form: workspace loads without collision diagnostic");
 
     let env = build_check_env(&ws);
     let candidates = env
@@ -59,18 +59,18 @@ fn mq3_class_class_collision_loads_clean_and_populates_candidates() {
     );
 }
 
-/// mq.3.5 (class-fn repurpose): the fixture
+/// Class-fn repurpose: the fixture
 /// `examples/test_22b2_method_name_collision_class_fn.ail.json`
-/// declares `class Greet { greet }` and `fn greet`. Pre-mq.3 this
+/// declares `class Greet { greet }` and `fn greet`. Pre-canonical-class-form this
 /// fired `WorkspaceLoadError::MethodNameCollision { kind: "class-fn" }`.
-/// Post-mq.3 the workspace loads cleanly — the method-vs-fn
+/// Post-canonical-class-form the workspace loads cleanly — the method-vs-fn
 /// coexistence is now legal at load time; the call-site emits a
-/// `class-method-shadowed-by-fn` warning (covered by mq.3.6 E2E,
+/// `class-method-shadowed-by-fn` warning (covered by the multi-class E2E,
 /// not this load-level pin).
 #[test]
 fn mq3_class_fn_collision_loads_clean() {
     let entry = examples_dir()
         .join("test_22b2_method_name_collision_class_fn.ail");
     load_workspace(&entry)
-        .expect("post-mq.3: workspace loads — class-vs-fn name overlap is no longer a load error");
+        .expect("post-canonical-class-form: workspace loads — class-vs-fn name overlap is no longer a load error");
 }