refactor(DT-3906): Simple Svelte 5 migrations

[tegan-temporal]

Description & motivation 💭

We want to (eventually) have all our code in Svelte 5 syntax.

This PR migrates components where the migration is very straightforward.

• No named slots
• No event handlers

Testing 🧪

Manual smoke testing all changes should be 1:1 (no behavior changes).

How was this tested 👻

• Manual testing
• E2E tests added
• Unit tests added

Steps for others to test: 🚶🏽‍♂️🚶🏽‍♀️

Checklists

Draft Checklist

Merge Checklist

Issue(s) closed

Docs

Any docs updates needed?

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Project	Deployment	Actions	Updated (UTC)
holocene	Ready	Preview, Comment	May 1, 2026 4:58pm

[temporal-cicd]

Warnings

⚠️

📊 Strict Mode: 16 errors in 7 files (1.6% of 1002 total) src/lib/components/workflow-status.svelte (4) L47:22: Type 'string | null' does not satisfy the constraint 'string | number | symbol'. L133:16: 'count' is possibly 'undefined'. L134:9: 'count' is possibly 'undefined'. L137:13: Type 'null' cannot be used as an index type. src/lib/components/lines-and-dots/svg/history-graph.svelte (1) L73:11: Type 'EventGroup | undefined' is not assignable to type 'EventGroup'. src/lib/components/lines-and-dots/workflow-pending-task.svelte (5) L18:14: 'pendingTask' is possibly 'undefined'. L22:14: 'pendingTask' is possibly 'undefined'. L26:25: 'pendingTask' is possibly 'undefined'. L30:25: 'pendingTask' is possibly 'undefined'. L34:25: 'pendingTask' is possibly 'undefined'. src/lib/components/lines-and-dots/svg/workflow-row.svelte (2) L33:26: Type 'WorkflowStatus' is not assignable to type 'string | undefined'. L43:24: Type 'WorkflowStatus' is not assignable to type 'string | undefined'. src/lib/components/lines-and-dots/svg/graph-widget.svelte (2) L49:7: Type 'WorkflowExecution | undefined' is not assignable to type 'WorkflowExecution'. L50:27: Argument of type 'WorkflowExecution | undefined' is not assignable to parameter of type 'WorkflowExecution'. src/lib/i18n/translate.svelte (1) L20:43: Argument of type '{ count: number | undefined; }' is not assignable to parameter of type 'I18nReplace'. src/lib/holocene/user-menu-mobile.svelte (1) L16:4: Type 'string | undefined' is not assignable to type 'string'.

Generated by 🚫 dangerJS against 3eb0277

[andrewzamojc]

This LGTM. Nice choice of changes to keep it easy to review and not too many changes needed to consumers in cloud-ui.