Move shared types and utilities out of tensorzero-core into
tensorzero-inference-types, in preparation for extracting
crates/tensorzero-core/src/providers/ into a standalone
tensorzero-providers crate in a follow-up PR.

Moved (re-exported from core for backward compatibility):

- `InferenceProvider`, `WrappedProvider`, `TensorZeroEventError`
  from `tensorzero-core/src/inference/mod.rs` to a new
  `tensorzero-inference-types::provider_trait` module. The trait
  is the linchpin every provider implements; relocating it lets
  the providers crate live without depending on tensorzero-core.

- `BatchRequestRow` and `UnparsedBatchRequestRow` (plus their
  `sqlx::FromRow` impl for `PgRow`) into
  `tensorzero-inference-types`. The orphan rule means the FromRow
  impl had to follow the type.

- `deprecation_warning`, `is_mock_mode`, `get_mock_provider_api_base`
  into a new `tensorzero-inference-types::utils` module.

Also exposes `tensorzero-inference-types::serde_helpers` and adds
`deserialize_json_string` to it (needed by the moved BatchRequestRow).

Adds `async-trait` and `reqwest-sse-stream` as deps of
`tensorzero-inference-types`.

No behavior change. `cargo check --all-targets --all-features`
and `cargo clippy --all-targets --all-features -- -D warnings`
both pass.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

…-openai providers)

Create the `tensorzero-providers` crate and move the first batch of
provider files that have no dependency on `openai/`:

Moved:
- helpers.rs, helpers_thinking_block.rs, chat_completions.rs (foundation)
- aws_common.rs, aws_bedrock.rs, aws_sagemaker.rs
- anthropic.rs, gcp_vertex_anthropic.rs
- gcp_vertex_gemini/, google_ai_studio_gemini.rs

Remaining in core (depend on openai/ or core test infra):
- openai/, azure, deepseek, fireworks, groq, hyperbolic, mistral,
  openrouter, sglang, tgi, together, vllm, xai, dummy, test_helpers

Also:
- GCPVertexGeminiSupervisedRow refactored to own Vec<FunctionToolDef>
- Extension trait for building supervised rows from LazyRenderedSample
- From<&FunctionTool> for FunctionToolDef added in core
- Pre-commit exclusion for providers gcp_vertex_gemini test key
- warn_inference_parameter_not_supported + serialize_or_log added to
  tensorzero_inference_types::utils

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>