[AIGTWY-4881] Add CUJ 6 repeated-config E2E journey

[david-siqi-liu]

CUJ 6 (AIGTWY-4881, epic AIGTWY-4875) checks that a developer who receives successive admin configs ends up with exactly the latest one: no stale ug-managed values, and their own settings untouched. It runs live on main's dedicated-workspace CUJ framework (#1000) with the TUI request recorder (#994), against the CUJ 6 plan in the UG Configure E2E doc.

Workspace configs are read only, because parallel CI jobs share them. Each phase is the single published config of its own pre-provisioned workspace, and one shared home moves through them:

• A: dbc-8c38ce9b-634b, CUJ 1's config plus the named MCP ug_e2e.tools.fixture_reader
• B: dbc-175bc4a3-a511, Claude on the Bedrock MPS ug_e2e.providers.bedrock, Codex on UC discovery ug_e2e.models, Codex as the default agent
• C: dbc-998133ab-de86, Codex only, on the static list system.ai.gpt-5-6-luna

All three share one metastore, the ug_e2e fixtures, and one trace table. The test never writes workspace config; it checks each published config against the plan at the start and asserts it is unchanged at teardown. A to B to C also exercises ug's cross-workspace switch.

Builds on #1010 (merged), and on #1004 (merged), whose workspace_origin keeps the TUI request recorder's http://127.0.0.1:<port> origin for the workspace API calls CUJ 6 routes through it.

Changes:

• tests/e2e_cuj/test_cuj_repeated_config.py: one class, phases as ordered class-scoped fixtures (phase_a -> phase_b -> phase_c) returning frozen evidence, 28 small tests on top.
  • Setup: seeds user-owned Claude and Codex prefs, a user stdio MCP, and a hand-written skill, with no ug state.
  • Readback: each phase workspace publishes exactly the plan's config (agents, model sources, defaults, headers, tracing, MCP selector).
  • Phase A: configures twice; identical settings and registrations, no duplicates; both agents complete a task with their phase headers and default models at gateway ingress (recorder) and in the native turn.
  • Phase B: Claude carries databricks-model-provider-service and no Phase A headers; Codex carries databricks-model-service-parent-schema and only the Phase B header; request and turn models match the sources. Bare ug in a real terminal launches Codex and completes a task on ug_e2e.models.codex_primary, and writes the Phase B header into /etc/codex/managed_config.toml. Static picker, family defaults, tracing keys, static Codex catalog, and the managed MCP are gone and stay gone after launches. Codex emits a span; Claude emits none.
  • Phase C: configures in a terminal (Phase B's terminal launch made ug own the machine-wide files) and clears Phase B's headers from /etc. Codex requests carry no Phase B headers, the picker is exactly Luna, Codex and bare ug both run Luna, ug claude is rejected with no inference request, and no Codex span is emitted while the Phase B span proves the trace query works.
  • Every phase: user prefs, MCP registrations, and skill files are unchanged, and each agent's registered user MCP still starts and lists its tool.
• tests/e2e_cuj/helpers/constants.py: the CUJ 6 metastore fixtures. The Claude tracing keys come from ucode.agents.claude.CLAUDE_OTEL_TRACE_ENV_KEYS.
• tests/e2e_cuj/helpers/tui_request_recorder.py: retarget_session is public so a terminal configure can be retargeted to the recorder.

Known gaps (tracked in AIGTWY-4972):

• Managed skills are not covered: UC skill bundles can't be uploaded on these workspaces' Default Storage catalog (Files API HTTP 501).

Validation: ruff check and format pass; related unit tests pass. Live: E2E CUJs on this head passed 48 tests (CUJ 6's 28, plus CUJ 1, 2, 4, and 5) in 11m36s: https://github.com/databricks/unity-gateway/actions/runs/37567899055/job/112619786676

This pull request and its description were written by Isaac.

[github-actions]

UG review

The visible patch adds a cross-workspace, shared-home E2E journey and exposes recorder retargeting, with no production changes shown. The new test file is truncated, so its later phase fixtures and assertions could not be reviewed.

No actionable findings.

Some patches were unavailable or truncated to fit the review context. Treat this as a partial review.

Automated advisory review of 2911d8ca82cc using Lilly's UG review rubric. It does not approve or block this PR.

[david-siqi-liu]

Re the UG review finding on .github/workflows/e2e-cuj.yml:7:

• Added tests/integration/utils/** to the trigger in dd1693e. CUJ 6 imports its harness, terminal, evidence, and SQL helpers from there, so changes to them now run the journey.
• Not adding src/ucode/** yet. The journey takes about 7 minutes against one dedicated workspace and runs serialized across PRs, so every product PR would queue behind it. Until [AIGTWY-4901] Only remove a Codex model ug wrote #921 lands it would also fail on Phase B for every product PR. This is worth revisiting once CUJ runs get per-run workspace allocation.

[david-siqi-liu]

Follow-up: #998 landed a shared dedicated-cuj job in integration.yml that runs all of tests/e2e_cuj, so 0f80c82 drops this PR's .github/workflows/e2e-cuj.yml entirely. The trigger-path question no longer applies to this PR.