phase29aq(p3): expand split stdlib subsets

docs/development/current/main/10-Now.md

@@ -3,7 +3,7 @@
 ## Current Focus
 
 - Phase: `docs/development/current/main/phases/phase-29aq/README.md`
-- Next: Phase 29aq P3 (stdlib split/scan derivatives)
+- Next: Phase 29aq P4 (stdlib split/scan derivatives)
 
 ## Gate (SSOT)
 

docs/development/current/main/30-Backlog.md

@@ -5,7 +5,7 @@ Scope: 「次にやる候補」を短く列挙するメモ。入口は `docs/dev
 
 ## Active
 
-- Phase 29aq: `docs/development/current/main/phases/phase-29aq/README.md` (Next: P3 split/scan derivatives)
+- Phase 29aq: `docs/development/current/main/phases/phase-29aq/README.md` (Next: P4 split/scan derivatives)
 - JoinIR regression gate SSOT: `docs/development/current/main/phases/phase-29ae/README.md`
 - CorePlan hardening (docs-first): `docs/development/current/main/phases/phase-29al/README.md`
 

docs/development/current/main/design/coreplan-migration-roadmap-ssot.md

@@ -34,7 +34,7 @@ Related:
 ## 1.1 Current (active)
 
 - Active phase: `docs/development/current/main/phases/phase-29aq/README.md`
-- Next step: Phase 29aq P3 (stdlib split/scan derivatives)
+- Next step: Phase 29aq P4 (stdlib split/scan derivatives)
 
 ## 2. すでに固めた SSOT（再発防止の土台）
 

docs/development/current/main/phases/phase-29ae/README.md

@@ -20,6 +20,8 @@ Goal: JoinIR の最小回帰セットを SSOT として固定する。
 - ScanWithInit (stdlib index_of_string, VM): `phase29aq_string_index_of_string_min_vm`
 - Pattern2 (stdlib parse_integer, VM): `phase29aq_string_parse_integer_min_vm`
 - SplitScan (stdlib split, VM): `phase29aq_string_split_min_vm`
+- SplitScan (stdlib split char, VM): `phase29aq_string_split_char_min_vm`
+- SplitScan (stdlib split string, VM): `phase29aq_string_split_string_min_vm`
 - Pattern1 (stdlib to_upper, VM): `phase29aq_string_to_upper_min_vm`
 - Pattern5 (Break, VM): `phase286_pattern5_break_vm`
 - Pattern5 (strict shadow, VM): `phase29ao_pattern5_strict_shadow_vm`

docs/development/current/main/phases/phase-29aq/P3-SPLIT-SUBSET-EXPANSION-INSTRUCTIONS.md

@@ -0,0 +1,42 @@
+---
+Status: Done
+Scope: stdlib split subset expansion (char/string)
+Related:
+- docs/development/current/main/phases/phase-29aq/README.md
+- docs/development/current/main/phases/phase-29ae/README.md
+---
+
+# Phase 29aq P3: split subset expansion (stdlib coverage)
+
+Goal: expand stdlib split coverage with char and string delimiter fixtures and
+wire them into the JoinIR regression gate (phase29ae pack). Behavior is
+unchanged; inputs avoid empty segments.
+
+## Subsets (SSOT)
+
+- Char delimiter: `split("a b c", " ")` (single-character separator)
+- String delimiter: `split("a--b--c", "--")` (multi-character separator)
+
+Notes:
+- Empty segments are excluded by input in fixtures (no leading/trailing or
+  repeated delimiters).
+- No new Plan/Composer vocabulary; reuse existing SplitScan subset.
+
+## Fixtures / smokes
+
+- `apps/tests/phase29aq_string_split_char_min.hako`
+- `apps/tests/phase29aq_string_split_string_min.hako`
+- `tools/smokes/v2/profiles/integration/joinir/phase29aq_string_split_char_min_vm.sh`
+- `tools/smokes/v2/profiles/integration/joinir/phase29aq_string_split_string_min_vm.sh`
+
+## Gate wiring
+
+- Add both smokes to `tools/smokes/v2/profiles/integration/joinir/phase29aq_stdlib_pack_vm.sh`.
+- Ensure `phase29ae_regression_pack_vm.sh` runs the stdlib pack.
+- Update `docs/development/current/main/phases/phase-29ae/README.md`.
+
+## Verification
+
+- `cargo build --release`
+- `./tools/smokes/v2/run.sh --profile quick`
+- `./tools/smokes/v2/profiles/integration/joinir/phase29ae_regression_pack_vm.sh`

docs/development/current/main/phases/phase-29aq/README.md

@@ -58,7 +58,8 @@ Plan/Composer subsets (or mark unsupported) before adding new subsets.
 
 - P1: Add stdlib subsets in priority order (index_of/last_index_of → parse_integer → split).
 - P2: Add stdlib subsets (index_of_string → to_upper).
+- P3: Expand split subsets (char/string delimiters; empty segments excluded by input).
 
 ## Next (planned)
 
-- P3: Expand split/scan derivatives (candidate: starts_with/ends_with).
+- P4: Expand split/scan derivatives (candidate: starts_with/ends_with).