fix: add supported platforms

[andrew-bekhiet-solid]

Summary by CodeRabbit

• New Features
  • Added explicit support declarations for Android, iOS, Linux, macOS, web, and Windows platforms.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro Plus

Run ID: d8a18836-55b4-4568-b029-08db419ba6a4

📥 Commits

Reviewing files that changed from the base of the PR and between 41971cf and 481079f.

📒 Files selected for processing (1)

• pubspec.yaml

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📝 Walkthrough

Walkthrough

Changes

Platform support

Layer / File(s)	Summary
Declare supported platforms pubspec.yaml	Adds a top-level platforms block listing Android, iOS, Linux, macOS, Web, and Windows.

Estimated code review effort: 1 (Trivial) | ~2 minutes

Suggested reviewers: solid-danylosafonov

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title accurately summarizes the main change: declaring supported Flutter platforms.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch add-supported-platforms

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_{Comment @coderabbitai help to get the list of available commands.}

[illia-romanenko]

LGTM