docs: reorganize Orleans documentation navigation - #10336

Pull request overview

Reorganizes the Orleans documentation site into updated task/operations/architecture/migration/streaming tracks, updates navigation and samples entry points, and adds explicit legacy URL redirects which preserve anchors for retired pages.

Changes:

• Updates DocFX → Starlight sidebar generation to support absolute site-root links (for example, /samples/) and adjusts tests accordingly.
• Adds explicit redirect mapping (redirects.json) and integrates it into the legacy redirect generator and rendered-output audit.
• Large-scale docs refresh: adds new Orleans 10 operational, migration, streaming, and runtime-architecture pages while removing legacy/retired tutorials and platform guidance (for example, Service Fabric/Cloud Services content and older snippet projects).

Copilot's findings

• Files reviewed: 126/223 changed files
• Comments generated: 1

Copilot's findings

• Files reviewed: 129/256 changed files
• Comments generated: 0 new

Copilot's findings

function outputPathFor(route) {
  const relativeRoute = decodeURIComponent(route.slice('/orleans/'.length));
  const outputPath = relativeRoute.endsWith('/')
    ? path.resolve(distRoot, relativeRoute, 'index.html')
    : path.resolve(distRoot, relativeRoute);
  const relativeOutput = path.relative(distRoot, outputPath);
  if (relativeOutput.startsWith(`..${path.sep}`) || path.isAbsolute(relativeOutput)) {
    throw new Error(`Compatibility path '${route}' resolves outside the output directory.`);
  }
  return outputPath;
}

• Files reviewed: 129/256 changed files
• Comments generated: 1

Copilot's findings

• Files reviewed: 129/256 changed files
• Comments generated: 2

Copilot's findings

• Files reviewed: 134/262 changed files
• Comments generated: 0 new

Copilot's findings

• Files reviewed: 134/262 changed files
• Comments generated: 0 new

Copilot's findings

• Files reviewed: 134/262 changed files
• Comments generated: 0 new

Copilot's findings

• Files reviewed: 134/263 changed files
• Comments generated: 0 new

Copilot's findings

• Files reviewed: 134/263 changed files
• Comments generated: 0 new