refactor: tighten comments across #830 changes for clarity

- pluginRegistryPredicates.ts: consolidate 8-line JSDoc to 5 lines,
  removing redundant detail that restated implementation mechanics
  already obvious from the code.

- GraphWorkspace.tsx: shorten the lastScrubberMsRef comment from 5 lines
  to 2; trim the handleDiagnosticsChange block comment by removing the
  'rather than bailing out' implementation-alternative sentence; tighten
  the distanceVisual inline comment.

- pluginRegistry.temporal.test.mjs: replace 17-line file-level JSDoc
  with 9 lines focused on the invariant rather than the root-cause
  narrative (already covered in pluginRegistryPredicates.ts); remove
  two tsx loader implementation-detail comments; tighten two test-level
  inline comments.

No logic, types, or test assertions changed. All 42 tests pass.

explorer/src/workspaces/GraphWorkspace/pluginRegistryPredicates.ts

@@ -2,14 +2,9 @@
  * shouldLoad predicates for the GraphWorkspace lazy plugin registry.
  *
  * Extracted into a pure module so the predicates can be unit-tested without
- * importing the full GraphWorkspace React component (which depends on sigma,
- * React hooks, and browser globals). The corresponding registry entries in
- * GraphWorkspace.tsx must use these functions directly.
- *
- * These predicates gate WHEN each plugin's module is lazily imported.
- * None of them reference temporalState — temporal scrubber updates must not
- * retrigger plugin loading (see issue #830 for the render-loop that resulted
- * from the temporal-overlay entry originally reading temporalState?.currentTime).
+ * importing the full GraphWorkspace React component. Each predicate gates
+ * whether a plugin's module is lazily imported; none reference temporalState
+ * so temporal scrubber updates never retrigger plugin loading (issue #830).
  */
 
 export type PluginShouldLoadContext = {