Prepare 0.7.0 release

[leehack]

Summary

• Fold the remaining Unreleased entries into 0.7.0 and reorganize the long release notes into user-facing groups.
• Update the website recent-release summary so it matches the canonical changelog.
• Add release-doc coverage for the WebGPU bridge readiness globals and LiteRT-LM template registry discoverability.

Validation

• ./tool/docs/validate_links.sh
• git diff --check
• dart pub publish --dry-run (Package has 0 warnings)

Notes

• pubspec.yaml was already set to 0.7.0.
• Runtime behavior is unchanged by this PR; this is release-note and documentation prep only.

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 80.57%. Comparing base (e905df8) to head (8f420e7).

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #193   +/-   ##
=======================================
  Coverage   80.57%   80.57%           
=======================================
  Files          85       85           
  Lines       11392    11392           
=======================================
  Hits         9179     9179           
  Misses       2213     2213           

Flag	Coverage Δ
unittests	80.57% <ø> (ø)

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[Copilot]

Pull request overview

Prepares the 0.7.0 release documentation by consolidating changelog content, updating the website’s recent-release highlights to match the canonical changelog, and adding/clarifying release-doc coverage for WebGPU bridge readiness globals and LiteRT-LM template registry behavior.

Changes:

• Folded remaining “Unreleased” notes into 0.7.0 and reorganized CHANGELOG.md into user-facing groups.
• Updated the website “Recent Releases” summary to reflect the canonical 0.7.0 changelog highlights.
• Documented WebGPU bridge readiness globals/promise and LiteRT-LM .litertlm template registry discoverability/override guidance.

Reviewed changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
website/docs/platforms/webgpu-bridge.md	Updates readiness checklist and adds readiness globals/promise guidance and console probe.
website/docs/guides/chat-template-and-parsing.md	Adds a LiteRT-LM template registry section and points to the maintained registry doc.
website/docs/changelog/recent-releases.md	Refreshes the 0.7.0 highlight bullets to align with CHANGELOG.md.
doc/webgpu_bridge.md	Adds a “Bridge Readiness Signal” section documenting the readiness globals/promise.
CHANGELOG.md	Removes “Unreleased” and restructures release notes under 0.7.0 into grouped sections.

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