fix(tsconfig): do not throw when "extends"/"references" cannot be resolved

[dgozman]

Summary

• Reverts the hard error from fix(tsconfig): fail loudly when extends/references can't be resolved #41571 (docs change kept): our tsconfig resolution does not repeat the whole process tsc has (node_modules walk-up, package.json "exports" maps, directory-form project references), so unresolved "extends"/"references" are silently ignored again, with a TODO to implement tsc-compatible resolution.
• Adds regression tests for all reports in the issues.

Fixes #41989
Fixes #41998

[github-actions]

Test results for "tests 1"

7 flaky

⚠️ [chromium-library] › library/video.spec.ts:356 › screencast › should work for popups `@frozen-time-library-chromium-linux`
⚠️ [chromium-library] › library/video.spec.ts:664 › screencast › should capture full viewport `@chromium-ubuntu-22.04-arm-node20`
⚠️ [chromium-library] › library/video.spec.ts:495 › screencast › should capture static page in persistent context @smoke `@chromium-ubuntu-22.04-node20`
⚠️ [chromium-library] › library/video.spec.ts:736 › screencast › should work with video+trace `@chromium-ubuntu-22.04-node22`
⚠️ [firefox-page] › page/page-emulate-media.spec.ts:144 › should keep reduced motion and color emulation after reload `@firefox-ubuntu-22.04-node20`
⚠️ [firefox-page] › page/page-goto.spec.ts:81 › should work with Cross-Origin-Opener-Policy `@firefox-ubuntu-22.04-node20`
⚠️ [playwright-test] › ui-mode-test-output.spec.ts:118 › should collapse repeated console messages for test `@windows-latest-node22`

50724 passed, 1190 skipped

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Merge workflow run.

[github-actions]

Test results for "MCP"

1 failed
❌ [firefox] › mcp/dashboard.spec.ts:108 › should activate session when show is called with -s @mcp-windows-latest-firefox

7807 passed, 1266 skipped

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Merge workflow run.

[github-actions]

🟢 CI is clear — the one failure is a known pre-existing flake

Hi, I'm the Playwright bot and I triaged the CI failures here.

This PR only touches tsconfig extends/references resolution (tsconfig-loader.ts + resolver.spec.ts). The single failing test is an MCP dashboard test that never exercises that code path, and it flakes on the same bot across many unrelated PRs. Nothing here looks caused by this PR.

Details

Overall: 1 failure, on the MCP suite only; tests 1 reported 7 flaky and 0 real failures. The diff is confined to test-runner tsconfig resolution and doesn't reach any MCP or accessibility code.

Pre-existing flake / infra

• [firefox] › mcp/dashboard.spec.ts:108 › should activate session when show is called with -s (mcp-windows-latest-firefox) — pre-existing flake, not this PR. In the aggregated CI results this exact (project, file, title) on this bot failed 22 of 239 runs (~9%), passed the other 217, spanning 109 different PRs. The identical error signature (expect(locator).toHaveAccessibleName(expected) failed on a getByRole locator) shows up on 14 other PRs (feat(test-runner): support named test locks #41862, fix: correct pending navigation log spacing #41949, test(chromium): fixme flaky "should ignore page.pause when headed" on macOS #41959, feat: add pierceFrames() locator API #41963, fix(mcp): reconnect to the browser after disconnect #41966, feat(reporter): add omitTags option to omit auto-appended tags #41968, feat(chromium): roll to r1235 #41974, feat(webkit): roll to r2339 #41975, Revert "chore(deps-dev): bump fast-uri from 3.1.3 to 3.1.4" #41978, chore(deps): bump postcss from 8.5.16 to 8.5.23 #41983, fix(aria): preserve names from collapsed text contributors #41988, chore(test-runner): record videos via the screencast API instead of recordVideo #41995, test: roll stable-test-runner to 1.63.0-alpha-2026-07-27 #41999, Revert "chore: roll stable test runner to 1.62.0-beta-1784842988000" #42003) plus several push runs — none of which could involve this branch. It fails only on the Windows + Firefox MCP bot; every other MCP bot (200 PRs each) is green, which points at a bot/engine-specific timing issue rather than product code.

Recent final-verdict history for this test on mcp-windows-latest-firefox (oldest→newest, 🟩 pass / 🟥 fail):

🟩🟥🟩🟥🟩🟩🟥🟥🟩🟥🟥🟩🟥🟥🟩🟥🟩🟥🟩🟥🟩🟥🟥🟥🟥🟥

Flaky (retried green, no action)

• 7 flaky in tests 1 (video screencast on chromium, page-emulate-media/page-goto on firefox, ui-mode-test-output on windows) — all unrelated to tsconfig resolution.

_{Triaged by the Playwright bot - agent run}