chore(release): prepare v26.6.3

[mekilis]

Summary

Prepares the v26.6.3 patch release.

• Bump VERSION to v26.6.3.
• Add the CHANGELOG.md section for everything landed since v26.6.2:
  • feat(billing): render cloud plans dynamically for three-tier pricing (feat(billing): render cloud plans dynamically for three-tier pricing #2710)
  • feat(controlplane): print user/org ids and optionally mint an api key on bootstrap (feat(controlplane): print user/org ids and optionally mint an api key on bootstrap #2712)
  • fix(billing): send org owner email on cloud trial start to backfill legacy billing email (fix(billing): send org owner email on cloud trial start to backfill legacy billing email #2709)

Docs/metadata only. Tag v26.6.3 will be pushed at the merge commit to trigger the image build and release.

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Note

Low Risk
Docs and version metadata only; no runtime or security behavior changes in this diff.

Overview
Bumps VERSION from v26.6.2 to v26.6.3 and adds a CHANGELOG.md section for that release, listing the features and fixes already merged since 26.6.2 (billing cloud plans, bootstrap API key/IDs, billing email backfill).

No application or infrastructure code changes—metadata only so tagging v26.6.3 at merge can drive image build and release.

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