Closes the v0.10 carl.camp parity arc and ships it to PyPI. carl-studio
0.18.3 → 0.20.0 (major-minor bump for the entitlements + AXON + slime
+ ledger surface). carl-core 0.1.2 → 0.2.0 (9 new error subclasses +
set_global_forwarder seam in interaction.py).

Bumps:
  pyproject.toml                                     0.18.3 → 0.20.0
  src/carl_studio/__init__.py                        0.18.3 → 0.20.0
  packages/carl-core/pyproject.toml                  0.1.2  → 0.2.0
  packages/carl-core/src/carl_core/__init__.py       0.1.2  → 0.2.0
  uv.lock                                            regenerated

CHANGELOG.md: full v0.20.0 entry under [0.20.0] — 2026-05-09 — v0.10
carl.camp parity. Lists every new module, error code, CLI command,
test count, and cross-repo touch point. Existing [Unreleased] section
preserved (covers v0.18 / v0.19 work that landed pre-merge).

Tag push order (per CLAUDE.md release flow):
  1. carl-core@0.2.0
  2. v0.20.0
Subpackage tag MUST go first; pushing v0.20.0 before carl-core@0.2.0
publishes leaves carl-studio install-broken on PyPI (carl-core 404 at
install time).