Promote managed AnsiString from opt-in to default

• Type: feature
• Status: done
• Owner: Codex
• Blocked-by: bug-managed-byref-string-param-store, feature-managed-exception-cleanup
• Opened: 2026-06-06 (from todo.md §2d / §4)

Motivation

AnsiString now uses the heap-backed, refcounted, copy-on-write representation by default. The frozen fixed-capacity inline ABI remains available with -uPXX_MANAGED_STRING for compatibility testing.

Scope

Plan: ../../developer/plan-refcounted-compiler-strings.md. Delivered:

• PasInitDefines seeds PXX_MANAGED_STRING by default.
• make bootstrap and make test use the managed default path.
• make test-frozen, make test-nilpy-frozen, make bootstrap-frozen, and make stabilize-frozen keep an explicit -uPXX_MANAGED_STRING opt-out lane.
• Stale docs and the exact frozen hello-size assertion were updated for the new default.

User direction (memory): wants per-use string typing / right-sizing, not a blunt global flip.

Acceptance

Managed strings selectable as default with all ownership paths covered; compiler self-host fixedpoint holds under the managed default; BSS drops accordingly.

Log

• 2026-06-12 — Done by Codex. make bootstrap produced a managed-default fixedpoint (bss=133040256B, down from the frozen ~1.67 GB scale); make test, make test-nilpy, make fpc-check, make test-frozen, and make symbols pass.
• 2026-06-12 — Added benchmark coverage for both Hello World output modes. Sanity run: managed-default hello = 24,665 bytes; frozen -uPXX_MANAGED_STRING hello = 287 bytes.
• 2026-06-12 — Claimed by Codex; starting managed-string default packaging/reseed work.
• 2026-06-06 — ticket opened from todo.md §2d/§4.