fix(examples-py): validate Mirascope, Mistral, and Ollama OTel 2.x spans

[Nightingalelyy]

Summary

• add a committed Mirascope 2.x call, sync/async stream, tool, privacy, expected-error, and live-gateway example set
• expand Mistral examples with deterministic sync/async streaming, connected tool execution, provider 401, and application 500 coverage
• harden Ollama examples with semantic workflow inputs, connected tool execution, deterministic 503 coverage, client/server teardown, and an aggregate runner
• preserve one exact shell marker across all subprocesses and flush/shut down Respan explicitly

Validation

• Ruff format/check and Python compilation pass for all three example directories
• Ollama example-contract tests: 3/3
• exact marker: otel2-fix-py-group-19-20260817T152514Z
• complete processes: Mirascope 5/5, Mistral 8/8, Ollama 5/5 (18/18)

Platform verification

The exact marker returned 19 traces and 42 records. Every trace tree and every full record was inspected: one root per trace, exact parent links, 42 unique record IDs, 42 unique span IDs, complete bounded inputs/outputs, exact stream flags and usage, canonical tool schemas/calls/results, controlled 401/500/503 failures, grouping, privacy, and no forbidden aliases.

Known external boundaries

Canonical tool attributes still do not populate the platform's separate top-level tool arrays, and native failed workflow roots are projected as success/200 after ingestion. Provider identity projection is also blank for Mirascope/Ollama despite canonical provider metadata. No contribution-contract aliases or package-specific ingestion workarounds were added.

Companion instrumentation PR: respanai/respan#385