chore(release): prepare 1.0.0-beta.7

[leoafarias]

Description

Prepare naked_ui 1.0.0-beta.7 for publication after the slider visual-percentage API merged in #79. This bumps the package version and adds a curated changelog entry for NakedSliderState.visualPercentageOf.

After this PR is merged and every check is green, the exact squash-merge commit will receive the lightweight tag v1.0.0-beta.7. Pushing that tag triggers the Android and web release gates followed by OIDC publication to pub.dev.

Related Issues

• Includes feat(slider): add NakedSliderState.visualPercentageOf #79.

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Checklist

• Existing tests for the released API are already on main; this PR changes release metadata only.
• The changelog and package version are updated.
• The release archive passes flutter pub publish --dry-run with zero warnings.
• I am prepared to follow up on review comments in a timely manner.

Breaking Change

Does this PR require users of the package to manually update their code?

• Yes, this is a breaking change.
• No, this is not a breaking change.

Validation

• fvm dart run melos ci — formatting clean, analysis clean, all tests passed across both packages.
• fvm flutter pub publish --dry-run — passed with 0 warnings.

[github-actions]

LCOV of commit ac8f9ed during Flutter CI #267

	(use "lcov --ignore-errors deprecated,deprecated ..." to suppress this warning)
Reading tracefile /tmp/__zgosalvez_github-actions-report-lcov/lcov.info.
Summary coverage rate:
  source files: 22
  lines.......: 89.6% (2945 of 3287 lines)
  functions...: no data found
  branches....: no data found
Message summary:
  1 warning message:
    deprecated: 1

Files changed coverage rate: n/a