fix(testing): reconcile ORCH-116 with merged ORCH-123 (ADR renumber, CHANGELOG, env parity)

Recovery from the merge-gate rebase-conflict bounce. The feature branch was
rebased onto origin/main (which had merged ORCH-123). The single conflicting
hunk — docs/architecture/README.md — was resolved during the rebase: kept
ORCH-123's host-side staging-runner line AND the ORCH-116 test-runner bullet.

This follow-up commit reconciles the remainder:

- Renumber the global sweeping ADR adr-0049 -> adr-0050. ORCH-123 took adr-0049
  (adr-0049-host-side-docker-execution-boundary.md) on main while ORCH-116 was
  in flight, so ORCH-116 yields to the merged task and moves to the next free
  number. Mechanical cross-reference reconciliation only (git mv + title + every
  test-runner reference across README/internals/CLAUDE/CHANGELOG/config.py +
  06-adr/ADR-001 + 12-review). Main's adr-0049 host-side references are left
  byte-for-byte untouched. No design/verdict content was altered.
- Restore the ORCH-116 CHANGELOG entry that the CHANGELOG auto-merge silently
  dropped (both ORCH-123 and ORCH-116 inserted at the same [Unreleased] anchor;
  git kept only ORCH-123).
- Add the missing ORCH_TEST_RUNNER_* keys to .env.example (parity with the
  ORCH_STAGING_RUNNER_* block; ORCH-101 canon of start keys).

Refs: ORCH-116

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

docs/architecture/adr/adr-0050-deterministic-test-runner.md

@@ -7,7 +7,7 @@ created_at: 2026-06-16
 model_used: claude-opus-4-8
 ---
 
-# adr-0049: Детерминированный test-раннер — второй реализованный срез determinization-roadmap (tester-гибрид)
+# adr-0050: Детерминированный test-раннер — второй реализованный срез determinization-roadmap (tester-гибрид)
 
 > **Сквозной (cross-cutting) ADR.** Агрегирует решение ORCH-116, влияющее на **весь**
 > оркестратор: вводит новый компонент-leaf `src/test_runner.py`, снимает вторую avoidable

docs/architecture/internals.md

@@ -109,7 +109,7 @@ LLM). Leaf `src/staging_runner.py` (зеркало `run_deploy_finalizer`) ис
 `self_deploy.map_exit_code_to_status`, пишет `15-staging-log.md` (тот же machine-key `staging_status:`)
 и вызывает существующий `advance_stage(finished_agent="deployer")` (см. §5). Так LLM-агент `deployer`
 на `deploy-staging` исчезает из happy-path; `STAGE_TRANSITIONS`/`QG_CHECKS`/схема БД не тронуты.
-**ORCH-116 ([adr-0049](adr/adr-0049-deterministic-test-runner.md)):** тем же паттерном (рядом с
+**ORCH-116 ([adr-0050](adr/adr-0050-deterministic-test-runner.md)):** тем же паттерном (рядом с
 ORCH-115) перехватывается джоб `tester` на стадии `testing` для in-scope репо с тест-контрактом
 (дискриминатор — роль `tester` **И** `tasks.stage == "testing"` **И** `test_runner.applies(repo)` под
 kill-switch `test_runner_enabled`, скоуп `test_runner_repos`, резолв `_has_test_contract`; пусто →