Resolves High and Medium findings from the test-quality audit. No source code
changes — only test files. Baselines preserved or improved:

  b2c-cli:          1218 → 1224 passing
  b2c-tooling-sdk:  1722 → 1717 passing (0 pending; -13 tautological smokes,
                                          +2 substantive tests, +6 previously
                                          silently-skipped tests now run)
  b2c-dx-mcp:       720  → 720  passing

Highlights:
- Removed mock theater: webdav `buildPath` SUT-stubs, openapi-fetch passthrough
  comparisons, and "client creation" `to.exist` smokes that TypeScript already
  proved.
- SCAPI command tests for "displays/logs in non-JSON mode" now capture stdout
  and assert on rendered content; renderer is no longer stubbed.
- Replication 422/409 errors, sites "no sites" copy, content/validate real-
  validator path, job `--show-log` invocation are now actually verified.
- e2e tests: replaced `oneOf([0,1])` and conditional-assertion patterns with
  deterministic asserts; code-lifecycle delete captures version id before
  clearing; sandbox delete follows up with a `get` 404 check; AM error tests
  match real SUT messages; dead `hasProject` skip gate removed.
- SDK pagination tests either iterate properly or are renamed to match what
  they actually verify; `oauth-jwt`, `auth/middleware`, watcher `stop()`,
  base-command telemetry-skip, and plugin loader tests now assert on
  observable behavior rather than `to.not.throw`.
- `MobifySource` tests use proper DI in place of `Object.defineProperty(os,
  'homedir')` skip-on-fail; logs integration `beforeEach` fails loudly under
  `process.env.CI`.
- MCP `addTool` registration tests intercept `registerTool` and invoke wrapped
  handlers; site-theming filter test verifies the asked question is excluded;
  page-designer-decorator regex tightened to deterministic strings; services
  tests assert OAuth wiring and base URLs.

…ration

The repo's CI does not provision a live B2C instance — the logs integration
suite is genuinely opt-in and skipping is the correct behavior when the
prerequisite is unavailable. Reverts the over-zealous "fail loud under CI"
change introduced earlier in this PR.

Per @patricksullivansf review: the safeParse / isOptional / enum-value
checks were testing Zod itself, not the tool's contract. Keep field-presence
assertion only.