Establish the published 4.8.1 Python text API contract

[sidmohan0]

The Rust migration needs a reproducible baseline of what the released Python package actually does. This freezes 111 black-box observations from the published datafog==4.8.1 wheel and checks the development checkout against them without regenerating expectations.

The cases cover structured synchronous detection, Unicode offsets, selection and aliases, allowlists, German locale activation, explicit-span overlap handling, all legacy transformation strategies, result shapes, selected signatures, warnings/errors, convenience APIs, guardrails, and regex TextService calls. The migration guide separates 102 compatibility cases from nine observations requiring review, including invalid-checksum cards and mismatched explicit span text. ML, OCR, Spark, CLI, async, and application-adapter acceptance remain explicitly outside this baseline's scope.

The capture tool requires isolated imports, verifies the pinned PyPI wheel SHA-256 and installed package bytes, and writes only a separate candidate file. The existing CI test discovery automatically includes the contract suite. Detection and transformation behavior are unchanged. The nlp-advanced extra now explicitly includes SentencePiece and protobuf so the multilingual GLiNER tokenizer can load without the OCR extra. Its install-profile smoke test also checks that the tokenizer protobuf schema loads.

Validation:

• Published wheel: 111/111 observations matched; independent recapture reproduced the full fixture.
• Checkout contract: 111 passed on Python 3.10, 3.12, and 3.14.
• Contract plus engine, bridge, allowlist, German PII, agent, and telemetry suites: 260 passed.
• Altered-wheel rejection and deliberate mismatch detection verified.
• All applicable configured pre-commit hooks passed.
• Reproduced the missing-protobuf error with Transformers 5.16.1, then loaded and exercised the actual microsoft/mdeberta-v3-base tokenizer after installing protobuf.

[CLAassistant]

All committers have signed the CLA.