fix(examples-py): validate Ragas, Replicate, and Restate OTel 2.x spans

[Nightingalelyy]

Summary

• Add deterministic, current-SDK example suites for Ragas and Restate and repair the existing Replicate suite.
• Preserve the exact shared marker, use bounded semantic workflow inputs, keep committed requirements registry-portable, and guarantee flush/shutdown plus aggregate timeout reporting.
• Validate modern Ragas metrics/evaluation/experiments, Replicate sync/async/stream/lifecycle/error behavior, and registered Restate workflow/service/error paths against local editable packages.

Validation

• Full example diffs were audited against every applicable document under respan/contribution/; portable dependency, lifecycle, marker, privacy, and package-boundary rules have no remaining example-owned violation.
• Example contract tests pass: Ragas 3/3, Replicate 3/3, Restate 3/3 (9/9).
• Root-scoped Ruff check and format-check pass for all 26 changed example files.
• Local editable direct_url.json entries resolve Ragas, Replicate, and Restate to the paired Respan workspace packages.
• All 11 example processes completed under exact marker otel2-fix-py-group-24-20260818T031547Z.
• Respan MCP opened all 11 trace trees and all 30 full record details: one root per trace, exact parentage, 30 unique log IDs and span IDs, complete content/status/stream/lifecycle data, exact marker fields, and no aliases, credentials, addresses, or duplicates.

External follow-ups

• Decorated workflow roots above the failed Replicate 429 and Restate 500 children retain error messages but are projected as success/200; the package children and trace error counts are precise.
• Replicate live-provider coverage remains credential-gated, and a real Restate server/protocol/replay boundary requires an external runtime.
• Full-detail ingestion omits canonical entity-path projection and reports the Replicate model owner as provider ID despite canonical gen_ai.system=replicate.

Companion examples

• respan #390