chore: bump genui and genui_a2a to 0.10.0 and sync CHANGELOGs

[jacobsimionato]

Description of Changes

• Bumps genui pubspec.yaml version from 0.9.2 to 0.10.0 and syncs CHANGELOG.md header from ## 0.10.0 (in progress) to ## 0.10.0.
• Bumps genui_a2a pubspec.yaml version from 0.9.0 to 0.10.0 and syncs CHANGELOG.md header from ## 0.10.0 (in progress) to ## 0.10.0.
• Updates consumer dependency constraints across workspace packages (dev_tools/catalog_gallery, dev_tools/composer, examples/simple_chat, examples/verdure/client, tool/e2e) from ^0.9.0 to ^0.10.0 to satisfy monorepo workspace verification checks.

Rationale

Ensures pubspec.yaml versions match CHANGELOG.md release headers so that CI publication health checks (dart-lang/ecosystem firehose rules) pass without version out-of-sync errors.

Testing / Running Instructions

Run dart run tool/test_and_fix/bin/test_and_fix.dart locally or inspect CI validation checks.

[gemini-code-assist]

Code Review

This pull request bumps the version of the genui and genui_a2a packages to 0.10.0, finalizes their changelogs, and updates all dependent examples, tools, and packages to use the new ^0.10.0 version. I have no feedback to provide.

[github-actions]

Package publishing

If you have publishing permissions, you can use the links below to publish the changes after merging this PR.

Package	Version	Status	Publish tag (post-merge)
package:a2ui_core	0.0.1-wip002	ready to publish	a2ui_core-v0.0.1-wip002
package:genai_primitives	0.2.4	ready to publish	genai_primitives-v0.2.4
package:genui	0.10.0	ready to publish	genui-v0.10.0
package:genui_a2a	0.10.0	ready to publish	genui_a2a-v0.10.0
package:json_schema_builder	0.1.5	already published at pub.dev

Documentation at https://github.com/dart-lang/ecosystem/wiki/Publishing-automation.

[jacobsimionato]

@polina-c this fixes an issue I was seeing on previous PRs e.g. #990 (comment)