iter cma.1: master mini-spec + render binary for cross-model authoring experiment

New top-level experiments/2026-05-12-cross-model-authoring/ (out of
root Cargo workspace; nested-crate standalone via empty [workspace]
table per Cargo idiom). The renderer projects one canonical
master/spec.md into two form-specific files (rendered/json.md and
rendered/ailx.md) by walking three directive forms ({form-only:
json}, {form-only: ailx}, {example: <id>}) and emitting per-example
fenced blocks sourced from 13 curated .ail.json fixtures.

Four test gates green (10/10 total):
- splitter_unit (7) — directive parser, malformed inputs panic
- spec_completeness (1) — AST-variant visitor lifted verbatim from
  schema_coverage.rs; 34/34 variants covered by the curated subset
- example_roundtrip (1) — every fixture roundtrips through
  ailang_surface::{print, parse} to identical canonical bytes
- token_balance (1) — form-only block totals balanced to 3.22% under
  tiktoken-rs::cl100k_base (gate is ±5%)

Six of the 34 variants did not have a dedicated fixture topic in the
plan and were absorbed into the closest existing fixture per the
plan's Step 4.14 escape hatch (Let/Clone → fn_calls_prelude; LetRec
→ data_with_match; If → match_literal_pattern; ReuseAs →
data_simple; Const → floats). Surfaced as a journal note, not a
plan revision.

Two ancillary additions vs. plan, both structural Cargo necessities,
spec-compatible: render/Cargo.toml carries an empty [workspace] table
so the nested crate refuses parent-workspace discovery, and
render/.gitignore drops /target + Cargo.lock. Both surfaced inline
in the per-iter journal's Concerns section.

cma.2 (harness) and cma.3 (live IONOS run + DESIGN.md addendum +
journal + roadmap edits) remain out of scope per the spec.

bench/orchestrator-stats/2026-05-12-iter-cma.1.json

@@ -0,0 +1,23 @@
+{
+  "iter_id": "cma.1",
+  "date": "2026-05-12",
+  "mode": "standard",
+  "outcome": "DONE",
+  "tasks_total": 9,
+  "tasks_completed": 9,
+  "reloops_per_task": {
+    "1": 0,
+    "2": 0,
+    "3": 0,
+    "4": 0,
+    "5": 0,
+    "6": 0,
+    "7": 0,
+    "8": 1,
+    "9": 0
+  },
+  "review_loops_spec": 0,
+  "review_loops_quality": 0,
+  "blocked_reason": null,
+  "notes": "Task 8 token_balance failed on first run (json=1800, ailx=1692, ratio 6.00%); one substantive AILX-side spec.md edit brought it to 3.22%. Counts as 1 re-loop on Task 8 (implementer-phase repair, not a review-loop)."
+}