[Refactor/Chore] Replace low-value Web tests with behavioral coverage #44259

Problem

The Web suite contains substantial coverage of rendering defaults, CSS classes, repeated branches, pass-through wrappers, and mocked implementations of the behavior under test. These tests make refactoring expensive while allowing regressions in permissions, timers, editor state, and asynchronous data flow to go unnoticed.

Proposed change

Review the existing unit and browser suites across Web, remove low-value assertions and redundant suites, and retain tests at the component, feature, or service boundary that owns the observable contract. Use real stores, generated query options, interactive primitives, and editor integration where those own the behavior; isolate external services and expensive independent boundaries.

Fix reproducible product bugs discovered during the cleanup and retain focused regressions. Examples include plugin installation countdown cleanup, single-node run permissions, OAuth trigger composition, streaming chunk boundaries, variable defaults and removal, workflow cycle handling, and comment keyboard interaction.

Verification

Run the complete Web unit and browser projects, repository static checks, and Web tsslint. The accompanying draft PR will report the completed results and follow CI through to completion. Coverage remains a diagnostic signal rather than an acceptance target.