docs: add wiki pages for all audiences, fix .old.yml leak

9 new wiki pages: getting-started, faq, troubleshooting,
advanced-usage, verification-modes, adding-a-platform,
adding-a-scraper, testing-guide, release-process.

Updated architecture.md with mermaid diagrams, tools.md with
full pipeline and target/exporter sections, profiling.md with
missing fields, index.md with glossary and nav links.

Expanded CONTRIBUTING.md from stub to full contributor guide.

Filter .old.yml from load_emulator_profiles, generate_db alias
collection, and generate_readme counts. Fix BizHawk sha1 mode
in tools.md, fix RetroPie path, fix export_truth.py typos.

scripts/common.py

@@ -683,6 +683,8 @@ def load_emulator_profiles(
     if not emu_path.exists():
         return profiles
     for f in sorted(emu_path.glob("*.yml")):
+        if f.name.endswith(".old.yml"):
+            continue
         with open(f) as fh:
             profile = yaml.safe_load(fh) or {}
         if "emulator" not in profile: