Improve release-notes prompt for version-aligned companion packages

[apoorvdeshmukh]

What changed

• Added a Branch Model section: release notes are maintained on main, but version/dependency/source files must be read from the target release branch (they can differ).
• Reworked Version and Dependency Lookup to be branch-aware. Documented the two real layouts — Centralized (tools/props/Versions.props, release/6.1–release/7.0) vs Per-package (src/**/Versions.props, main/7.1+) — and a git ls-tree/git show discovery approach instead of hardcoded paths.
• Added a Package Registry note that the package set varies by branch (e.g., release/6.1 has no extensions or Internal.Logging), with instruction to verify a package exists on the branch before generating notes.
• Reconciled the skip rule with version alignment: 7.0.2+ companion packages (AzureKeyVaultProvider, Extensions.Azure, Extensions.Abstractions, Internal.Logging) get release notes on every aligned core release even with no functional changes, using a version-alignment-only style. Microsoft.SqlServer.Server stays independently versioned.
• Added a step to cross-link companion package notes from the core MDS release notes, and added that section to 7.0.2.md so the published GitHub release retains companion context.
  Why
• Companion packages now version-align with MDS but keep their own release notes; the prompt's version-source paths were stale and its guidance didn't account for branch-specific layouts, missing packages on older branches, or alignment-only releases.

No functional/code changes — documentation/prompt only.

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[Copilot]

Pull request overview

Updates the repository’s release-notes Copilot prompt to be branch-aware and to properly handle version-aligned companion packages, and adds cross-links from the core 7.0.2 release notes to the companion package notes.

Changes:

• Documented the “release notes on main / shipped source on release branch” model and made version/dependency lookup instructions explicitly branch-aware.
• Updated the prompt’s skip/generation rules to include alignment-only companion package releases (7.0.2+), plus added guidance to cross-link companion notes from core MDS notes.
• Added a “Companion package release notes” section to release-notes/7.0/7.0.2.md linking to aligned companion package notes.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
release-notes/7.0/7.0.2.md	Adds links to the aligned companion package 7.0.2 release notes from the core 7.0.2 notes.
.github/prompts/release-notes.prompt.md	Reworks the prompt to be branch-aware and to explicitly include alignment-only companion package release notes and cross-linking guidance.

[paulmedynski]

Looking for commentary on my idea.

[paulmedynski]

Could we put this prompt on each branch and tailor it for that branch? Perform the generation on the branch, with a PR targeting that branch, and then just forward-port the results to main once they merge. That might be simpler and more intuitive than trying to explain our 3 different branch layouts, versioning schemes, packages, etc all in this prompt.