[Waterfall] Handle empty or incomplete Waterfall data

[mossy426-cdc]

Story Key: waterfall-view:handle-empty-data

User Story

As a MicrobeTrace user, I want to handle empty or incomplete data in the Waterfall view, so that I can recover from missing data without a broken view.

Workflow / Use Case

Open the Waterfall view with empty, filtered, or incomplete data and verify the app shows a coherent empty or recovery state.

Expected Behavior

Waterfall presents clear empty-state behavior and avoids stale rendered data when no valid rows, nodes, links, or fields are available.

Acceptance Criteria

• Given the linked QA tracker scenarios, when the user performs the covered Waterfall workflow, then the expected behavior remains true for each listed fixture and spec.
• Given the listed Cypress specs are run, when they pass, then this story has automated evidence for the grouped acceptance checks.
• Given linked QA evidence changes, when this story is regenerated, then tested fixtures, specs, and coverage notes stay aligned with the current QA trackers.

QA Tracker Evidence

• waterfall-view:W019
• waterfall-view:W024

Tested Against

Fixtures

• n/a
• AngularTesting_Epi_linklist_BS.csv

Cypress Specs

• cypress/e2e/journeys/flows/waterfall-empty-state.cy.ts

Coverage Notes
Grouped from 2 QA tracker row(s): No-data prompt; Filtering hides every visible cluster and recovery via Reveal Everything. Source areas: Waterfall Empty State.

Source References

• User story row: docs/user-stories.csv#L97
• Branch: dev
• Commit: f4b481eb2242d2a89251300c3b94eaf09c842e04
• Generated by: mossy426-cdc
• Epic / Feature Group: Waterfall
• Story Type: Data Processing
• Priority: P1
• Story Review Status: Draft
• Source Confidence: High
• Last reviewed: 2026-04-22

Story Notes

Generated as a grouped user story from QA tracker evidence. Review title and behavior language before enabling story_sync.

Definition of Done

• Acceptance criteria are satisfied.
• Linked QA tracker evidence remains current.
• Relevant Cypress coverage remains passing or any coverage gap is documented.
• Expected behavior remains distinguishable from bug or enhancement requests.

Manual Notes

Reviewer notes added below this line are preserved by future sync runs.