iter design-md-rolesplit.1 (DONE 9/9): DESIGN.md -> design/ ledger role-split

The 3020-line docs/DESIGN.md is replaced by the design/ ledger:
design/INDEX.md (sole addressable spine, typed Contracts+Models tables,
polymorphic links — prose file OR authoritative source //!), 14
design/contracts/*.md test-linked invariants + 3 source-link-only
contracts (mangling/env-construction/qualified-xref, no prose file —
code is SoT), 5 design/models/*.md whitepapers, and
docs/journals/2026-05-19-design-decision-records.md (the
relitigation-guard archive — every why/rejected/does-not-do/rollback/
empirical ### moved out at ###-granularity). Clean cut: git rm
docs/DESIGN.md, no stub.

RED-first crates/ailang-core/tests/design_index_pin.rs — the 4-clause
anti-regrowth spine (DESIGN.md-gone / every-INDEX-link-resolves /
every-contract-names-a-resolvable-ratifier /
contracts-carry-no-decision-record-prose) — demonstrably RED before,
GREEN after. Build-atomic by task ordering: design_schema_drift.rs's
include_str! (the only compile-time consumer) retargeted to
design/contracts/data-model.md BEFORE the deletion; its
## Data model/## Pipeline slicer dropped (a simplification the split
enables). 2 NoInstance diagnostics + 2 lockstep E2Es retargeted to
design/contracts/{float-semantics,typeclasses}.md. ~12 agent reading
lists + 5 SKILL bodies + CLAUDE.md + skills/README.md + ~25
code/C/.ail/spec comment xrefs retargeted; OQ7 dangling 'Iter 13b'
cite deleted (no forward target — a pointer would be fiction).
honesty-rule.md rewritten so the rule names the new home
(rationale->journals), resolving the recon-found internal
contradiction; the two docs_honesty_pin.rs:70,72 pinned phrases kept
verbatim+contiguous.

Boss-verified independently: cargo test --workspace 646 passed /
0 failed; design_index_pin 4/4; acceptance grep CLEAN of live
DESIGN.md refs (residuals = only the spec-mandated clause-4
deletion-enforcer). 2 DONE_WITH_CONCERNS routed to the mandatory
milestone-close audit: (a) str-abi.md:23 '(iter str-concat,
2026-05-13)' provenance stamp trips advisory architect_sweeps Sweep-1
— Boss-confirmed byte-identical to DESIGN.md@deeffb1:2062-2065, a
faithfully-migrated PRE-EXISTING anchor (regexes verbatim, only path
retargeted), NOT split-introduced — RATIFY-or-tidy at audit; (b) a
now stale-direction intra-prose 'see Str ABI below' cross-ref in
float-semantics.md — audit-adjudication candidate. Plan defect noted:
Task 9 Step 4's verbatim acceptance grep used a ^./ anchor not
matching the system's grep -rIn output; substance re-verified CLEAN.

Spec grounding-check PASS x2. Journals INDEX + decision-records
pointer appended (Boss-only).

docs/journals/INDEX.md

@@ -114,3 +114,5 @@
 - 2026-05-19 — iter embedding-abi-m5.3 (DONE 3/3): final functional M5 iteration — the time-shard boundary-invisibility proof + friction harvest. One symbol (EURUSD), three disjoint contiguous single-month windows (2017-03/04/05), each folded on its own thread owning its own `Kernel` (`Ctx: !Send` ⇒ one-ctx-per-thread compile-time-enforced). Adds the purely-additive windowed adapter sibling `fold_window` (same `MidPriceStream`+`Kernel` path as `fold_symbol`, differs only by `stream_tick_windowed`), a new single-responsibility `[[bin]] timeshard_runner`, `chrono` as a **dev-dep** (the time-shard test derives `(y,m)→Unix-ms` bounds via data-server's own `NaiveDate…timestamp_millis()` precedent and passes raw ms to the bin, keeping the bin date-math-free and Invariant 1 untouched), and `tests/timeshard.rs` carrying the spec §3 strength-ordered assertions: (a) each shard's `(acc,n)` **bit-exact** vs a single-thread host fold of THAT EXACT window in data-server stream order — the first actual proof of the chunk/window-boundary-invisibility claim the entire M4 retirement rests on; (b) host-summed partials bit-exact by construction; (c) the whole-window [2017-03..2017-05] single-thread total within `REL_TOL=1e-6` only (cross-shard f64 re-association is host arithmetic, NOT a kernel property — asserting it bit-exact would be the bug; tolerance derived from the recursive-summation error bound with ~4 orders of safety, shown in the test). Plus the now-deterministic global leak-Σ (post-`dbd76e5`) and a journal-only friction-timing capture (no bench gate, no timing assertion — flake-free). RED was a genuine deterministic compile failure (declared-but-absent `[[bin]] timeshard_runner` source; surfaced as Cargo's missing-source error rather than the plan's predicted `env!` error — same root cause, same trigger, no false-green; recorded as a benign plan-text imprecision in Concerns). The shipped m5.2 symbol-fan path (`swarm_runner.rs`, `swarm.rs`) and m5.1 core stay byte-untouched and green. Boss-verified independently: **timeshard determinism 5/5** (consistent ~2.7s, no jitter); full ail-embed suite **0 failed AND 0 ignored** across all binaries (lib 2, swarm 2 — the m5.2 leak-proof stays un-ignored & green, the whole saga's resolution intact —, smoke 1, rt_archive 1, timeshard 1); isolated `embed_rc_global_stats_race` still green; AILang workspace `cargo metadata` data-server count 0; compiler-surface diff empty (zero diff to crates/ailang-*, crates/ail/, runtime/, examples/*.ail, root Cargo.toml, DESIGN.md). **Friction-harvest deliverable (P2 flat-array-decision input): host-per-tick-FFI ≈ 658 ms / 3 192 562 ticks ≈ ~206 ns/tick at real EURUSD volume.** M5's functional work is complete; the milestone closes next via the mandatory `audit` (which also handles the pre-existing `docs/DESIGN.md:2358-2360` "additive M4 concern" drift, explicitly out of m5.3 scope). → 2026-05-19-iter-embedding-abi-m5.3.md
 - 2026-05-19 — audit embedding-abi-m5 (milestone close): DRIFT (one doc-honesty tidy) + RATIFY (gc_rss trio, evidenced) + causally-exonerated pre-existing P2 bench noise. Architect: **Invariant 1 PASS** (zero data-server in any compiler crate/runtime; ail-embed its own workspace root; only "finance" hits are the M3 ABI export *symbol name* — ABI not data-server knowledge), M3 frozen-layout SSOT unmoved (the lone rc.c change `7bfa11e` touched only the global stats counters), rc.c header-comment honesty accurate; drift = `[medium]` DESIGN.md:2358-2360 stale "additive M4 concern" (PRE-EXISTING, M4 retired, correctly scoped out of M5) + `[medium]` DESIGN.md §"Embedding ABI" silent-drift (it asserts "no shared mutable runtime state … data-race-free" but the now-atomic global RC-stats fallback IS shared mutable state under concurrency — M5 is AILang's first concurrent consumer) + `[low]` rc.c:88 "two unconditional ++" imprecise — one tidy, same honesty axis, not split. Bencher (my pre-audit "gc_rss is allocator-orthogonal → environmental" hypothesis was **refuted by evidence** — the verification discipline working): the 3× `*.gc_rss_kb +32%` are GENUINE, DETERMINISTIC, M5-attributable — `7bfa11e`'s atomic split a branch in `ailang_rc_alloc` (reached by GC programs via `str.c` int→str at `print`), spilling `%r14/%rbx`; a stale interior list pointer in the new spill slot is conservatively retained by Boehm, pinning a ~32 MB dead spine (Boehm collection #12 freed PRE 32 MB vs HEAD 32 B); bisects exactly on the commit, IR byte-identical, `ail` sha256-identical; RC/bump RSS dead-stable. `bump_s`/`max_us` = pre-existing tracked-P2 (bump RC-orthogonal; max_us 1-sample tail-jitter, PRE often worse, +65→+104% swing between runs minutes apart — dispositively noise), NOT M5. Adjudication: **RATIFY** the gc_rss trio — language reason (Decision 9: Boehm is explicitly transitional; the cost is purely a Boehm conservative-scan false-retention artifact on the transitional allocator of a *correct, necessary, user-approved swarm-safety fix*, codegen-layout-fragile, RC path the committed model and unaffected; chasing it with an out-of-scope codegen change invests in the path being removed) — selective baseline re-anchor `bench/baseline.json` lines 14/44/64 ONLY (137448/137768/137636, bencher-confirmed steady-state; every other metric byte-pristine — a wholesale --update-baseline would have absorbed the P2 noise and broken the established-envelope discipline); re-run confirms the 3 now `ok` at ±0.3%. **NO-ratify / causally exonerated** for bump_s×2 + max_us×2 — baseline pristine, identical disposition to the M2/M3/prelude-decouple closes. Friction-harvest recorded (P2 input): host-per-tick-FFI ≈ ~206 ns/tick at real EURUSD volume. M5 closes after the doc-honesty tidy lands + Boss-verified. Ratify discipline honored: updated baseline JSON + this paired JOURNAL ratify entry committed together. → 2026-05-19-audit-embedding-abi-m5.md
 - 2026-05-19 — iter embedding-abi-m5.tidy (DONE 3/3): resolves the M5 milestone-close audit DRIFT (28ab56a). DOC/COMMENT-ONLY, recon-pin-verified, single cohesive commit (M2.tidy a80d495 / M3.tidy 63d7d60 precedent — pins are the coverage, no RED, no audit/fieldtest gate). `docs/DESIGN.md` edit-1 §"Free (host side)": dropped the retired-M4 forward-reference ("an additive M4 concern, not a contradiction of this freeze" — M4 retired 2026-05-18) → present-tense current fact (a boxed-field record is **not** an M3 embedding type, export-gate-rejected; the freeze covers exactly the all-scalar single-ctor record). edit-2 §"Embedding ABI": reconciled the now-inaccurate "(no shared mutable runtime state — … data-race-free, sanitiser-verified)" blanket with the real post-7bfa11e state — the per-allocation hot path (per-ctx counters + per-object refcount header) is non-atomic by design and never shared (`Ctx: !Send`, single-thread-per-ctx); the one datum a multi-threaded host shares is the global RC-stats fallback counter, atomic-relaxed so the swarm's leak accounting is exact; "data-race-free, sanitiser-verified" retained (still true). `runtime/rc.c:88` 18g.0-block comment-only: stale "two unconditional `++` operations" → accurate "one counter bump per alloc/free … relaxed atomic add on the global null-ctx fallback, a plain `++` on the per-ctx path" (consistent with the adjacent already-correct :93-106 atomic block + :45-55 Threading header). Boss-verified independently: all pins green (design_schema_drift 8/0, docs_honesty_pin 5/0, effect_doc_honesty_pin 4/0, embed_record_layout_pin 1/0) — the mechanical proof the edits moved no pinned/hashed byte; the adjacent separately-pinned bare-scalar sentence is byte-identical (shifted 2299→2305 by net-added lines; `docs_honesty_pin.rs:135` is a substring pin, passes); rc.c diff strictly comment-only (filter empty); `cargo build --workspace` Finished; git scope = only docs/DESIGN.md + runtime/rc.c + journal/stats. Clears the M5-audit doc-honesty debt; no new debt. This is the FINAL M5 iteration — M5 (the M1–M5 Embedding ABI arc) is now functionally complete, audited, ratified, and doc-honest. → 2026-05-19-iter-embedding-abi-m5.tidy.md
+- 2026-05-19 — iter design-md-rolesplit.1 (DONE 9/9, whole milestone): the 3020-line `docs/DESIGN.md` replaced by the `design/` ledger — `design/INDEX.md` (sole addressable spine, typed Contracts+Models tables, polymorphic links: prose file OR authoritative source `//!`), 14 `design/contracts/*.md` test-linked invariants + 3 source-link-only contracts (mangling/env-construction/qualified-xref, no prose file — code is SoT), 5 `design/models/*.md` onboarding whitepapers, and `docs/journals/2026-05-19-design-decision-records.md` (the relitigation-guard archive: every why/rejected/does-not-do/rollback/empirical `###` moved out at `###` granularity). Clean cut (`git rm docs/DESIGN.md`, no stub). RED-first `crates/ailang-core/tests/design_index_pin.rs` 4-clause anti-regrowth spine (DESIGN.md-gone / every-INDEX-link-resolves / every-contract-names-a-resolvable-ratifier / contracts-carry-no-decision-record-prose) demonstrably RED→GREEN. Build-atomic by task ordering (the only compile-time consumer, `design_schema_drift.rs` `include_str!`, retargeted to `design/contracts/data-model.md` BEFORE the deletion; the `## Data model`/`## Pipeline` slicer dropped — a simplification the split enables). 2 NoInstance diagnostics + their 2 lockstep E2Es retargeted to `design/contracts/{float-semantics,typeclasses}.md` (the contiguity-across-`\`-continuation hazard scrubbed). ~12 agent reading lists + 5 SKILL bodies + CLAUDE.md + skills/README.md + ~25 code/C/.ail/spec comment xrefs retargeted to the Appendix destinations; OQ7 dangling "Iter 13b" cite deleted (no forward target — a pointer would be fiction). honesty-rule.md rewritten so the rule names the new home (rationale→journals), resolving the recon-found internal contradiction; the two `docs_honesty_pin.rs:70,72` pinned phrases preserved verbatim+contiguous. Boss-verified independently: whole `cargo test --workspace` **646 passed / 0 failed**, `design_index_pin` 4/4, acceptance grep **CLEAN of live DESIGN.md refs** (residuals = only the spec-mandated clause-4 deletion-enforcer), honesty-rule repair carries no clause-3 marker. Spec grounding-check PASS ×2 (one re-dispatch after a corrected commitment-4 pin-status claim; one after the Boss-adjudicated relocation-appendix amendment resolving plan-recon's 7 open questions — ledger completed to 17 contract rows incl. the qualified-xref/str-abi/scope-boundaries additions the 12-list under-counted). 2 DONE_WITH_CONCERNS routed to the mandatory milestone-close `audit`: (a) `design/contracts/str-abi.md:23` `(iter str-concat, 2026-05-13)` API-provenance stamp trips advisory `architect_sweeps.sh` Sweep-1 — Boss-confirmed **byte-identical to DESIGN.md@deeffb1:2062-2065**, a faithfully-migrated PRE-EXISTING anchor (sweep regexes verbatim, only the path retargeted), NOT a split-introduced regression — RATIFY-or-tidy at audit; (b) the now stale-direction `(see "Str ABI" below)` intra-prose cross-ref in `float-semantics.md` (the Appendix is heading-level; no task prescribes intra-prose cross-ref rewrite) — audit-adjudication candidate. One plan defect recorded (Task 9 Step 4's verbatim acceptance grep used a `^\./` anchor not matching the system's `grep -rIn` output; substance independently re-verified CLEAN). → 2026-05-19-iter-design-md-rolesplit.1.md
+- 2026-05-19 — design-decision-records (migration): relitigation-guard archive — every why/rejected/does-not-do/rollback/empirical ### moved out of the former docs/DESIGN.md by the design-md-rolesplit milestone. Companion to spec 2026-05-19-design-md-rolesplit. → 2026-05-19-design-decision-records.md