feat(web): derive timeline-list into canonical audit-grade event-stream timeline [SPRINT-029]

Rework the orphan TimelineListComponent into a canonical audit-grade
event-stream primitive for all mounted chronology surfaces.

Canonical event model (FE-TLD-001):
- TimelineEvent with id, timestamp (ISO-8601 UTC), title, description,
  actor, eventKind (info/success/warning/error/critical/neutral), icon,
  evidenceLink, metadata key-value pairs, and expandable detail payload
- Relative time for <24h, absolute UTC for >=24h, full ISO on tooltip
- Date grouping when events span multiple days

Derived primitive (FE-TLD-002):
- Vertical timeline with colored severity markers
- Deterministic UTC timestamp formatting
- Expandable detail sections with expand/collapse toggle
- Optional actor, metadata chips, and evidence links
- Loading skeleton and empty state
- Accessibility: role="feed", role="article", aria-labels, datetime attrs
- Content projection via ng-template for domain-specific rendering

Adopted on 3 surfaces (FE-TLD-003):
- incident-timeline: replaces bespoke inline timeline markers with shared
  component; preserves affected-services chips and correlated-events via
  expandable and content projection
- audit-timeline-search: replaces bespoke timeline rendering; preserves
  module/action badges via content projection
- releases-activity: replaces timeline view mode (was rendering duplicate
  table) with canonical timeline; preserves lane/env/outcome chips

Tests (FE-TLD-004): 32 focused tests covering event rendering, severity
markers, timestamp formatting, expandable toggle, loading/empty states,
date grouping, accessibility, and default fallbacks.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

docs/modules/ui/TASKS.md

@@ -24,7 +24,7 @@
 - `docs/implplan/SPRINT_20260308_026_FE_settings_information_architecture_rationalization.md`
 - [DONE] `docs/implplan/SPRINT_20260308_027_FE_page_header_context_header_derivation.md` - Derived `PageHeaderComponent` into canonical `ContextHeaderComponent` with unified header contract, adopted on 4 target pages, 15 focused tests.
 - [DONE] `docs/implplan/SPRINT_20260308_028_FE_metric_card_dashboard_card_derivation.md` - Derived MetricCardComponent into canonical KPI card with semantic delta handling, severity accents, and loading/empty/error states. Adopted on 3 dashboards (12 bespoke tiles replaced). 40 tests pass.
-- `docs/implplan/SPRINT_20260308_029_FE_timeline_list_audit_timeline_derivation.md`
+- [DONE] `docs/implplan/SPRINT_20260308_029_FE_timeline_list_audit_timeline_derivation.md` - Derived canonical audit-grade timeline-list primitive. Adopted on incident-timeline, audit-timeline-search, and releases-activity.
 - [DONE] `docs/implplan/SPRINT_20260308_030_FE_split_pane_list_detail_shell_consolidation.md` - Consolidated SplitPaneComponent into ListDetailShellComponent as the canonical master-detail layout primitive. Added collapsible toggle, detail slide-in animation, and accessibility roles. Adopted on signing-key-dashboard. SplitPaneComponent deprecated.
 - `docs/implplan/SPRINT_20260308_031_FE_witness_viewer_evidence_derivation.md`
 

docs/modules/ui/implementation_plan.md

@@ -17,6 +17,7 @@ Provide a living plan for UI deliverables, dependencies, and evidence.
 - The queued orphan batch currently spans `SPRINT_20260308_013` through `SPRINT_20260308_023` and is intentionally not marked active until product review approves staffing.
 - Newly queued follow-on planning sprints cover Settings information architecture rationalization plus UX derivation tracks for the orphan `PageHeaderComponent`, `MetricCardComponent`, `TimelineListComponent`, `SplitPaneComponent`, and `WitnessViewerComponent` (`SPRINT_20260308_026` through `SPRINT_20260308_031`).
 - Sprint `028` (MetricCardComponent derivation into canonical KPI card) is DONE. The shared `MetricCardComponent` now supports semantic delta direction (`up-is-good` / `up-is-bad` / `neutral`), severity accents, loading/empty/error states, and ARIA accessibility. Adopted on signals-runtime, search-quality, and delivery-analytics dashboards. See `docs/implplan/SPRINT_20260308_028_FE_metric_card_dashboard_card_derivation.md`.
+- Sprint `029` (TimelineListComponent derivation) is DONE. Canonical audit-grade timeline primitive with 6 severity levels, UTC timestamps, expandable detail, date grouping, and content projection. Adopted on incident-timeline, audit-timeline-search, and releases-activity. See `docs/implplan/SPRINT_20260308_029_FE_timeline_list_audit_timeline_derivation.md`.
 - Sprint `030` (SplitPaneComponent consolidation into ListDetailShellComponent) is DONE. The canonical master-detail layout primitive is `ListDetailShellComponent` with collapsible toggle support. `SplitPaneComponent` is deprecated. Adopted on signing-key-dashboard (trust-admin). See sprint file for contract details.
 - Sprint `014` (CopyToClipboard, InlineCode, TruncatePipe adoption) is DONE. See `docs/features/checked/web/orphan-copy-inline-truncate-adoption.md`.
 - Sprint `015` (FilterBarComponent adoption) shipped, then was partially rolled back on audit-family pages to restore lost filter semantics. See `docs/features/checked/web/filter-bar-unification.md` and `docs/features/checked/web/orphan-revival-regression-remediation-ui.md`.