PR_26175_DELTA_008: API client service coverage

[ToolboxAid]

Summary

Team Delta expands API client service coverage using the page/service testing model.

• Adds npm run test:service:api as a service-level lane.
• Reuses scripts/run-node-test-files.mjs.
• Keeps npm test as the site-wide/all-tests command.
• Adds API client coverage for server requests, tool helpers, repository clients, session logout, and public API URL handling.
• Fixes logoutSessionUser() to use the existing session server data boundary.

Validation

• node --check src/api/session-api-client.js PASS
• node --check tests/dev-runtime/ServerApiClientStandardization.test.mjs PASS
• npm run test:service:api PASS, 2/2 files and 13 tests
• Package command guard PASS
• Delta harness absence check PASS
• Delta-named command grep PASS, no matches
• git diff --check PASS

Reports

• docs_build/dev/reports/PR_26175_DELTA_008-api-client-service-coverage.md
• docs_build/dev/reports/codex_review.diff
• docs_build/dev/reports/codex_changed_files.txt
• ZIP: tmp/PR_26175_DELTA_008-api-client-service-coverage_delta.zip