docs: clarify manual route grouping examples

[sam-bretz]

Summary

• Make manual route grouping the primary SDK example entry point, with a path that says exactly what the example demonstrates.
• Add an explicit route-grouping tree and route map showing how one trace becomes two dashboard workloads.
• Move provider, framework, telemetry, execution, and fixture examples under clearly named integration categories.
• Update READMEs, package-relative paths, CI jobs, and example tests for the new tree.
• Preserve explicit route_source metadata from the earlier route workload change so developer-selected boundaries remain visible to classification.

Example tree

examples/
├── route-grouping/
│   └── content-generation/
│       └── one-trace-two-workloads/
│           ├── README.md
│           ├── main.py
│           └── routes/
│               ├── haiku-draft/README.md
│               └── haiku-review/README.md
├── integrations/
│   ├── providers/
│   ├── frameworks/vercel-ai/
│   └── telemetry/
├── execution/batch-first/
└── test-fixtures/fake-providers/

Validation

• TypeScript SDK: 303 passed via npm test.
• Python SDK: 494 passed, 2 skipped with the existing Google real-client test excluded because the installed local client bypassed its mock and attempted a live API request.
• Relocated Python example contracts: 3 passed.
• Relocated telemetry examples: 3 passed.
• Offline manual route-grouping check: 3 calls, 2 routes, 1 trace.
• OpenRouter and Vercel example package tests: passed offline.
• git diff --check: clean.

Live Gemini and self-hosted validation were not run because deployment credentials were not available.