docs(prompts): sync commit/pr guidance and Copilot settings (#44627)

## Summary of the Pull Request
- Clarified the PR-summary prompt to prepend a PR title and to reuse the
Conventional Commit rules from
`.github/prompts/create-commit-title.prompt.md`.
- Expanded the commit-title prompt with clearer purpose, inputs, and
Conventional Commit guidance.
- Added workspace Copilot chat settings in `.vscode/settings.json` to
point review/commit/PR generation at the repo prompt files.

e.g. for commit tile generation:
<img width="562" height="376" alt="image"
src="https://github.com/user-attachments/assets/ca11d117-e4ad-4d1e-abb7-2b4600690f45"
/>


## PR Checklist
- [ ] Closes: N/A
- [ ] Communication: N/A (prompt/settings maintenance)
- [ ] Tests: Not run (prompt/settings-only change)

## Detailed Description of the Pull Request / Additional comments
- The PR-summary workflow now directs PR title generation to the
existing commit-title prompt instead of duplicating rules, and places
the title above the filled template.
- The commit-title prompt now spells out required diff command, decision
steps, and Conventional Commit examples.
- VS Code Copilot chat settings ensure review, commit, and PR
description generation use the repository prompts consistently.

## Validation Steps Performed
- Not run (no product code changes)

.github/prompts/fix-spelling.prompt.md

@@ -10,8 +10,8 @@ description: 'Resolve Code scanning / check-spelling comments on the active PR'
 
 **Guardrails:**
 - Update only discussion threads authored by `github-actions` or `github-actions[bot]` that mention `Code scanning results / check-spelling`.
-- Resolve findings solely by editing `.github/actions/spell-check/expect.txt`; reuse existing entries.
-- Leave all other files and topics untouched.
+- Prefer improving the wording in the originally flagged file when it clarifies intent without changing meaning; if the wording is already clear/standard for the context, handle it via `.github/actions/spell-check/expect.txt` and reuse existing entries.
+- Limit edits to the flagged text and `.github/actions/spell-check/expect.txt`; leave all other files and topics untouched.
 
 **Prerequisites:**
 - Install GitHub CLI if it is not present: `winget install GitHub.cli`.
@@ -20,5 +20,6 @@ description: 'Resolve Code scanning / check-spelling comments on the active PR'
 **Workflow:**
 1. Determine the active pull request with a single `gh pr view --json number` call (default to the current branch).
 2. Fetch all PR discussion data once via `gh pr view --json comments,reviews` and filter to check-spelling comments authored by `github-actions` or `github-actions[bot]` that are not minimized; when several remain, process only the most recent comment body.
-3. For each flagged token, review `.github/actions/spell-check/expect.txt` for an equivalent term (for example an existing lowercase variant); when found, reuse that normalized term rather than adding a new entry, even if the flagged token differs only by casing. Only add a new entry after confirming no equivalent already exists.
-4. Add any remaining missing token to `.github/actions/spell-check/expect.txt`, keeping surrounding formatting intact.
+3. For each flagged token, first consider tightening or rephrasing the original text to avoid the false positive while keeping the meaning intact; if the existing wording is already normal and professional for the context, proceed to allowlisting instead of changing it.
+4. When allowlisting, review `.github/actions/spell-check/expect.txt` for an equivalent term (for example an existing lowercase variant); when found, reuse that normalized term rather than adding a new entry, even if the flagged token differs only by casing. Only add a new entry after confirming no equivalent already exists.
+5. Add any remaining missing token to `.github/actions/spell-check/expect.txt`, keeping surrounding formatting intact.