fix: preserve docs lineage hop counts across expansion

[ernestoongaro]

Resolves #16379

Problem

Selecting 3+ / +6 in the inline docs DAG and clicking Expand resets both controls to 1+ / +1. Closing the expanded view also loses its hop selections. The lens survives because it uses shared state, while each DAG initializes its hop controls locally.

Solution

Initialize each DAG's hop controls from the existing lineage store when its root matches the requested resource. This preserves upstream and downstream selections, including max, across expansion and closing. A different root still starts at 1+ / +1, including when recentering an already-mounted DAG.

Includes browser regression stories, a changie-generated changelog entry, and rebuilt web/dist/ assets so the fix ships in the dbt binary.

Validation

• The Expand regression failed against the original code at the missing 3+ control and passes with the fix.
• 17 browser tests passed across the inline, expanded, and base DAG stories, including Expand/Close and different-root reset coverage.
• 13 lineage store/data-hook unit tests passed.
• Scoped ESLint, pnpm build (TypeScript and Vite), built asset reference checks, and git diff --check passed.

Checklist

• I have read the contributing guide and understand what's expected of me.
• I have run this code in development, and it appears to resolve the stated issue.
• This PR includes tests, or tests are not required or relevant for this PR.
• This PR has no interface changes (macros, CLI, artifacts, configuration, or adapter interfaces).