[close - superseded by #24] docs: migrate recent updates from trunk-io/docs

[mintlify]

Summary

Migrate documentation changes from trunk-io/docs that landed after the last sync.

Changes

• Welcome copy (index.mdx): Soften quarantine description — fingerprinting is no longer described as a quarantining input. Ported from (Chore): Fix copy on welcome page docs#663.
• Monitors framework refresh (flaky-tests/detection/*, flaky-tests/management/test-labels.mdx): Document the new decoupled monitor/action framework. Each monitor (pass-on-retry, failure rate, failure count) now exposes an Action — either Classify test status (existing behavior) or Apply labels (new). Test labels page now documents automatic labeling from monitors and the dry-run flow. Ported from Document automatic label application from monitors docs#656.

Context

Picked up commits 19fa25d and 7546810 from trunk-io/docs (May 14, 2026) that postdate the last sync into this repo.

[samgutentag]

Verification status (2026-05-19): live

Verified: customers can use this. Ready to publish.

• Eng PRs: (Chore): Fix copy on welcome page docs#663 (welcome copy fix, merged 2026-05-14), Document automatic label application from monitors docs#656 (monitor framework docs, merged 2026-05-14)
• Flag: monitor action framework gated by showLabelActions (true in ts/apps/e2e/flags.json default)
• Signals: feature is the decoupled monitor/action framework with Apply Labels action; shipped weeks ago. This PR migrates already-live content from the old GitBook repo (trunk-io/docs) to the Mintlify repo (trunk-io/docs2).

Note: PRs #13 and #22 cover overlapping migration scope. Coordinate which one to merge.

[samgutentag]

Catchup check (2026-05-19): superseded by #24, recommend closing.

Compared this PR's tree against current main:

• 5 of 6 files are byte-identical to main. The 6th (flaky-tests/management/test-labels.mdx) has a single trivial diff: one anchor reads ../detection/index#dry-running-with-labels here versus ../detection/#dry-running-with-labels on main. Both forms resolve to the same page; not worth a PR.
• Main already contains commit 1900ac5 from PR docs: migrate monitor label actions and welcome copy from trunk-io/docs #24 (merged 2026-05-18, "docs: migrate monitor label actions and welcome copy from trunk-io/docs"), which migrates the exact same upstream sources ((Chore): Fix copy on welcome page docs#663 + #656).

Recommend closing. PR #22 covers the one remaining upstream PR (trunk-io/docs#657: delete stacked-pull-requests page) that #24 did not.