✨ Adds new prompts for auditing, converting controllers, and logging

Introduces several new markdown prompt files to enhance the
repository's capabilities. These include instructions for auditing
files, converting MVC controllers to Minimal API endpoints, and
refactoring inline logger calls to use LoggerMessage-generated
methods. This improves code quality and aligns with project
conventions.

.github/prompts/audit-instructions.prompt.md

@@ -0,0 +1,51 @@
+---
+description: "Audit .github/instructions/ and .github/skills/ for duplication, stale references, and unscoped or misscoped files."
+agent: "agent"
+---
+
+# Audit Instructions & Skills
+
+Walk every file under `.github/instructions/` and `.github/skills/` and produce a prioritised report of issues. Make no edits unless the user approves them after reading the report.
+
+## Steps
+
+### 1. Inventory
+
+List every `*.instructions.md` and every `**/SKILL.md`, plus `copilot-instructions.md` and any `*.prompt.md`.
+
+### 2. Per-File Checks
+
+For each instructions file:
+
+- `applyTo` glob exists and matches actual files in the repo (no dead globs).
+- `description` accurately reflects the content (no stale TOCs, no over-promises).
+- Content is project-specific — flag anything restating universal Markdown / C# / formatter rules, or duplicating the agent runtime (e.g., "work in parallel", "save to memory").
+- File defers to enforcement layers (`.editorconfig`, analyzers, `Directory.Build.props`) instead of restating their rules.
+- Cross-references point at files that exist.
+
+For each skill:
+
+- Frontmatter `name` matches the directory name.
+- `description` starts with the action and includes "Use when:".
+- Procedure steps are actionable, not narration.
+- Commands actually work against this repo's tool versions and config files.
+- Cross-skill references use relative paths.
+
+### 3. Cross-File Checks
+
+- Same rule defined in multiple files with different wording or severity → flag.
+- Topics not covered by any file but enforced via PR comments / convention → flag as candidate new file.
+- `applyTo` overlap that could cause conflicting guidance on a single file → flag.
+
+### 4. Report
+
+Produce a table sorted by priority (high / medium / low):
+
+| Priority | File | Issue | Suggested fix |
+
+End with two summary counts: total files inspected, total issues found.
+
+## Guardrails
+
+- Read-only by default. Apply fixes only if the user explicitly approves them.
+- When suggesting a fix, quote the exact lines to change so the user can decide without re-reading the file.