Observability presentation

@backplane-labs/backplane-observability-ui contains generic LogViewer, TraceList, TraceWaterfall, SpanDetails, AttributeTable, CorrelationLinks, StackTrace, SourceContext and ErrorDetails. It has no query client, error grouping engine, issue workflow or service deployment knowledge. English resources are exported as observabilityEnglish under backplane.observability.

Callers supply records with stable IDs and own query/loading/error/partial state. Log columns are virtualized, sortable/filterable and configurable through the shared data table. Selection is keyed by ID across updates. Search highlighting renders plain text, including markup from log bodies. Detail dialogs show original body, attributes and resource fields, with caller-owned surrounding-log and correlation callbacks. Correlation never derives a relationship from a namespace; trace/span IDs and explicit resource values pass to the caller unchanged.

Span timestamps are decimal Unix nanosecond strings. Formatting uses only the millisecond part for the timezone calendar and appends the original nine-digit fraction. Duration subtraction and waterfall offsets use bigint. Only the bounded relative percentage becomes a JavaScript number for CSS positioning. Invalid or reversed times are reported. Tree construction is iterative and repairs cycles, duplicate IDs and missing parents visibly. Depths over 64 are split into additional roots so the table renderer cannot recurse through an unbounded parent chain. Unique span records remain inspectable. A waterfall input represents one trace; IDs must be unique within it. Status text accompanies error coloring.

Span details include resource/attributes, events, links and correlation controls. Stack frames use a virtualized table. Activating a frame displays at most 21 caller-supplied source lines around its location. Source paths are text, never automatically fetched. Nested causes are limited to 50 and cycle checked; any truncation is explicit. Structured payloads use the lazy JSON viewer and preserve bigint as decimal text.

Storybook fixtures exercise 10,000 logs, 2,000 spans across two services, missing and cyclic parents, event/link details, source context and nested causes in both themes. Error queries and envelopes belong to platform-ui's Errors (errors.md); these components only present.

humanDuration formats nanosecond spans (850 ns, 12.4 µs, 3.21 ms, 1.50 s); spanForest and spanPosition are exported for custom trace views such as the platform TraceView.