Update dependency ubuntu to v26

[renovate]

This PR contains the following updates:

Package	Type	Update	Change
ubuntu	github-runner	major	24.04 → 26.04

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[mergify]

Merge Queue Status

• ✅ Entered queue — 2026-10-02 19:13 UTC · Rule: dependency-updates · triggered by merge protections
• ✅ Checks passed · on draft merge queue: checking #52 on main (67f9065) #55
• ✅ Merged — 2026-10-02 19:25 UTC · at 5a8225482363ebc3386bf6be35e2200f32293dc3 · merge-batch via merge queue: checking #52 on main (67f9065) #55

This pull request spent 12 minutes 20 seconds in the queue, including 1 minute 11 seconds running CI.

Required conditions to merge

• #approved-reviews-by >= 1
  • Update dependency ubuntu to v26 #52
• github-review-approved [🛡 GitHub repository ruleset rule main]
  • Update dependency ubuntu to v26 #52
• any of [🛡 GitHub repository ruleset rule main]:
  • check-success = @github-actions/Test
  • check-neutral = @github-actions/Test
  • check-skipped = @github-actions/Test