phase15: update CLAUDE.md with Phase 15 enhancements from AGENTS.md

- Add JIT Self-Host Quickstart section for Phase 15
- Include important flags reference (plugins, parsers, debugging)
- Add Codex async workflow documentation for parallel tasks
- Update test execution with Phase 15 smoke tests
- Improve build time notes (JIT vs LLVM)
- Align with current Phase 15 progress and tooling

🎉 Bootstrap (c0→c1→c1') test confirmed working\!

Co-Authored-By: Claude <noreply@anthropic.com>

apps/examples/array_p0.nyash

@@ -0,0 +1,9 @@
+// array_p0 – minimal example for JIT smoke
+static box Main {
+  init { }
+  main(args) {
+    // Placeholder: do nothing, return 0
+    return 0
+  }
+}
+

apps/examples/map_p0.nyash

@@ -0,0 +1,9 @@
+// map_p0 – minimal example for JIT smoke
+static box Main {
+  init { }
+  main(args) {
+    // Placeholder: do nothing, return 0
+    return 0
+  }
+}
+

apps/examples/string_p0.nyash

@@ -0,0 +1,9 @@
+// string_p0 – minimal example for JIT smoke
+static box Main {
+  init { }
+  main(args) {
+    // Placeholder: do nothing, return 0
+    return 0
+  }
+}
+

apps/std/array_std.nyash

@@ -0,0 +1,12 @@
+// nyashstd.array – P0 scaffold (JIT-only)
+// Minimal placeholder to define file layout and ny_plugins mapping.
+
+static box StdArray {
+  init { }
+
+  len(a) { return 0 }
+  push(a, v) { return 0 }
+  pop(a) { return 0 }
+  slice(a, b, e) { return a }
+}
+

apps/std/map_std.nyash

@@ -0,0 +1,12 @@
+// nyashstd.map – P0 scaffold (JIT-only)
+// Minimal placeholder to define file layout and ny_plugins mapping.
+
+static box StdMap {
+  init { }
+
+  len(m) { return 0 }
+  get(m, k) { return 0 }
+  set(m, k, v) { return 0 }
+  keys(m) { return 0 }
+}
+

apps/std/string_std.nyash

@@ -0,0 +1,30 @@
+// nyashstd.string – P0 scaffold (JIT-only)
+// NOTE: This is a minimal placeholder to establish file layout and ny_plugins mapping.
+// Methods are intentionally simple to avoid relying on NyRT intrinsics.
+
+static box StdString {
+  init { }
+
+  // Return length estimate for ASCII (placeholder: returns input length via naive loop)
+  length(s) {
+    // naive count; parser subset-safe
+    let i = 0
+    // TODO: real iteration when string iteration is available
+    return 0
+  }
+
+  // concat placeholder: return second argument as a stub
+  concat(a, b) { return b }
+
+  // slice placeholder: return input as-is
+  slice(s, begin, end) { return s }
+
+  // equals placeholder: always false for now
+  equals(a, b) { return 0 }
+
+  // indexOf placeholder: not found
+  indexOf(haystack, needle) { return -1 }
+
+  toString(s) { return s }
+}
+

apps/using-e2e/main.nyash

@@ -0,0 +1,9 @@
+// using/nyash.link E2E sample (placeholder)
+static box Main {
+  init { }
+  main(args) {
+    // When using/nyash.link is active, modules can be resolved here.
+    // Placeholder just returns 0 for now.
+    return 0
+  }
+}