Align release workflow with Standards blueprint

[lipkau]

Summary

• Align ConfluencePS release/build workflow with the canonical AtlassianPS Standards release blueprint using AtlassianPS.Standards 0.1.11.
• Pin Standards workflow actions to 6fe5d05db84cdd10c9e4284e235a8f359c9537ad with v0.1.11 comments, use resolve-release-tag/setup-powershell/build-release-notes, and feed GitHub Releases from the generated release notes body_path.
• Remove the old changelog-to-release configuration and source publish-time manifest ReleaseNotes through Get-AtlassianPSReleaseNotesFromChangelog.
• Add release blueprint drift guards and a local ConfluencePS release runbook that links back to the Standards blueprint.

Notes

• Reviewed prior ConfluencePS PR Align ConfluencePS workflow standards to v0.1.6 #240 and reused only the relevant release workflow/guard-test direction, not the broad unrelated module/test changes.
• Used JiraPS PR #694 / merge commit a18283c8 as the reference implementation.
• Normalized the current ConfluencePS release metadata from two-part 2.5 forms to v2.5.0/2.5.0 so Standards release-note parsing can validate the existing current tag format.

Validation

• actionlint .github/workflows/ci.yml .github/workflows/integration_tests.yml .github/workflows/release.yml
• Invoke-Pester -Path 'Tests/Tools/StandardsVersionConsistency.Unit.Tests.ps1'
• Invoke-Build -Task Lint
• Invoke-Build -Task Build, Test
• git diff --check

Release metadata preflight

• Invoke-Build -Task Build, SetVersion -VersionToPublish v2.5.0 reaches Standards changelog parsing successfully, then fails because PSGallery already has ConfluencePS 2.5.1 while the repository latest GitHub tag/source baseline is v2.5.0. This existing release-state mismatch must be resolved before a real release preflight can pass for a publishable version.