Broken anchors and paths in v2 release notes

## Summary

The link-checker on PR #7173 (CI run: https://github.com/influxdata/docs-v2/actions/runs/25182601351/job/73831436424) flagged 8 pre-existing broken links across the v2 release notes and adjacent content. All are anchor or path typos pointing at headings/pages that no longer exist (or never existed). None block the PR; this issue tracks them for separate cleanup.

## Broken links

All 7 anchor errors below are in `content/influxdb/v2/reference/release-notes/influxdb.md` (older release-notes sections referencing anchors that have since been renamed/removed):

- [ ] `#flux-location-support` — anchor not found in target page
- [ ] `#error-updates` — anchor not found in target page
- [ ] `/influxdb/v2/visualize-data/visualization-types/graph/#legend` — `#legend` not on graph viz page
- [ ] `/influxdb/v2/visualize-data/dashboards/control-dashboard/#refresh-a-single-dashboard-cell` — anchor not on control-dashboard page
- [ ] `/flux/v0/release-notes/#v0-104-0` — Flux release-notes anchor not found
- [ ] `/flux/v0/release-notes/#v0-99-0` — Flux release-notes anchor not found
- [ ] `/flux/v0/release-notes/#v0-95-0` — Flux release-notes anchor not found

Plus one wrong-namespace path; couldn't locate the source page in `content/` via grep, so likely template-generated or in a data file:

- [ ] `/influxdb/cloud-serverless/reference/urls` — wrong namespace; cloud-serverless lives under `/influxdb3/`. Should resolve to `/influxdb3/cloud-serverless/reference/urls/` or be removed if the link is no longer relevant.

## Suggested approach

For the release-notes anchor errors, decide per case: either fix the anchor to point at the actual current heading (preferred where the target intent is clear), or unlink the prose if the linked content no longer exists. None of these are blocking incidents — they're old release-notes references that drifted as the surrounding docs evolved.

For the cloud-serverless namespace path, search build templates / `data/` for the source.

## Provenance

- Surfaced by the link-checker job on PR #7173.
- Confirmed pre-existing via `git blame` (sample: `#admin-token` in `restore.md` was added in `c32e05175`, 2026-01-27 — already fixed in PR #7173).
- This issue tracks the **remaining** errors not addressed in PR #7173.

Start with content/influxdb/v2/reference/release-notes/influxdb.md and review the link-checker results from PR #7173 for the seven anchor errors. Search build templates and data/ for the cloud-serverless URL source, then verify each link's target before correcting or removing it. Done means all eight tracked links resolve or are intentionally unlinked and the link checker passes.

Written by the indexing model from the issue text.