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>
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