fix(core): [CORE-SUBTITLE-OFFSET-01] refresh paused native cue membership and order

refactor/changes/2026-09-14-CORE-SUBTITLE-OFFSET-01-paused.md

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+# CORE-SUBTITLE-OFFSET-01: paused subtitle timing invalidation
+
+Baseline: b5dee252d461f91389c282a47401c5f8fd9a4483. Independent core correction
+discovered during PKG-MULTI-SUB-05; that package combination task remains doing.
+
+## Reproduction and implementation
+
+Firefox155 keeps cues in native activeCues after a paused offset changes their
+start/end outside currentTime. At paused time1.5, cues moved from1..3 to2..4
+still render. The old5.4.0 core and pre-change candidate both fail. A native
+HTMLVideoElement/TextTrack probe with no Artplayer instance reproduces the stale
+membership. Chromium153 and Windows WebKit26.6 have separate recorded observations.
+The first script-created-track probe did not become active on WebKit; the final
+probe uses a loaded HTML track matching the real integration, and records this
+fixture correction. Its initial overly precise seek assertion was corrected to
+require the actual1..2 interval; candidate offset tests separately compare each
+synchronous read against the pre-edit time.
+
+`subtitle/timing.ts` owns a small synchronous native invalidation step. After
+changing cue bounds, the existing offset mixin passes the native track, optional
+media capabilities and captured cue array. If paused and native membership/order
+differs from cue intervals at currentTime, remove and re-add the original cue
+objects in that order. Disabled tracks, playing media, missing capabilities and
+already-correct native state do not enter this path. No polling, timer, observer,
+new public option, UA sniffing, media seek or replacement cue is introduced.
+
+The first attempted mode-toggle correction fixed membership but reversed tied
+captions on a subsequent negative offset. That failing candidate report is retained;
+the final reinsertion implementation preserves order through1,-1,0,-3,0 offsets.
+Original cue bounds, identities, track mode and playback time remain. Update,
+notice and the public subtitleOffset event keep their existing synchronous order
+and values. Native cuechange/enter/exit notification can now reflect the corrected
+active membership, which is an intentional consequence of fixing stale activity.
+There is no new owned resource or disposal path.
+
+## Verification and scope
+
+Exact hashes, browser versions, logs, native state and artifact maps are recorded in
+[subtitle-offset-validation.json](../baselines/subtitle-offset-validation.json).
+
+- Five new controlled regressions join the existing subtitle suite: stale/missing
+  members, order drift, cue identity, update/event ordering, correct overlap,
+  disabled/playing/capability-limited hosts. The six-file core group passes58 tests.
+- Strict core and root consumer TS checks pass. Public generated declarations remain
+  unchanged:37 files checked,0 drift. Runtime helper types are internal only.
+- Expanded source browser run153:150 passing assertions,3 failures. Two failures
+  are old WebKit core5.3.0/5.4.0 source switching and remain task05 risks; the third
+  was the diagnostic seek precision assumption explained above. Candidate offset,
+  lifecycle and combination checks pass. The run includes explicitly labelled old
+  defects and must not be presented as153 successful compatibility acceptances.
+- Actual main build:15 passing cases comprise9 native probes,3 published behavior
+  observations and3 candidate offset regressions. Actual legacy build:3 candidate
+  offset cases pass. Candidate tests also cover disabled tracks and resumed play.
+- Three core formats and docs copies are rebuilt. The normal core build clears the
+  dist directory, so build:i18n regenerates all11 languages; those bytes remain
+  unchanged. Actual import/SSR/i18n distribution checks pass5 tests. CI regression
+  passes50 tests. Lint retains only its existing docs declaration warning.
+
+Published Firefox defects remain explicit in the offset and combination suites;
+only the candidate's assertion changes from failing to correct. The independent
+old-host overlap and WebKit source-switch issues are not waived or resolved here.
+No physical-device, full package, remote CI or publication acceptance is claimed.
+No dependency, lockfile, public declaration, version or package entrypoint change.
+
+## Maintenance and rollback
+
+Change timestamp invalidation in timing.ts and property bounds/notice behavior in
+player/subtitleOffsetMix.ts. Keep the native probe independent of player instances.
+Run node --test test/subtitle.test.js, strict core/root tsc, and the subtitle-offset,
+subtitle-lifecycle and multiple-subtitles-combinations browser suites. For actual
+artifact testing use the existing ARTPLAYER_BROWSER_ARTIFACTS map and include both
+core and chapter mappings, as required by the shared fixture server.
+
+Revert the dedicated task commit, including build outputs, to remove this correction.
+This is a local commit only, with no push or npm publication authorization.