Honor OTEL service identity and release PyFly v26.10.06

[ancongui]

PyFly's implicit service-name: ${pyfly.app.name} default and explicit SDK resource assignment masked the service identity injected by the platform. Workloads such as core-flydocs, core-flydocs-worker, and core-flydocs-bbox-worker consequently exported traces and metrics under the same pyfly-app name.

Remove that implicit override and resolve newly created trace/metric provider identity through the shared helper: explicit nonempty PyFly service-name override, then the SDK's standard OTEL_SERVICE_NAME / OTEL_RESOURCE_ATTRIBUTES handling, then application name and pyfly-app. Preserve other resource attributes, SDK parsing, custom/global providers, and provider ownership.

Add a real local OTLP/HTTP regression matrix that emits spans and counters, decodes both protobuf payloads, and checks precedence, defaults loading, empty values, encoded attributes, and neighboring resource attributes. Six scenarios failed before the fix; all eleven pass afterward. Synchronize versions to v26.10.06 (package 26.10.6), active download links, README badge, configuration/observability documentation, and both book editions. Explain explicit overrides and the need to restart existing providers.

Validation:

• Full Python 3.12 suite: 9,201 passed, 7 existing skips, 86% coverage. Ruff, 1,648-file formatting check, strict mypy across 817 source files, and dependency consistency passed.
• Actual OTLP payload matrix: all 11 cases passed after 6 reproduced failures; extended observability/admin/actuator/server checks: 93 passed.
• Independent review: no actionable P0/P1/P2 findings; reviewer independently passed 16 transport/ownership tests and reviewed the complete docs/version diff.
• Strict MkDocs, 83 book tests, both 31-file manuscript checks, metadata/lock consistency, shell syntax and wheel/sdist build passed. Final release books will be rebuilt from the tag and downloaded/verified.

Exact-head CI passed on d5ebb02: Python 3.12/3.13, SQLAlchemy 2.0, lint/types, documentation, package build, browser and installed distributions. Both candidate PDF/EPUB editions were built and their covers and changed identity pages visually reviewed. No production deployment or historical telemetry mutation is included.

Closes #151.