fix: read a 429's limit type from the API's detail

[makegov-mark]

What

Error::RateLimit's limit_type now reports which limit a 429 hit, "daily" or "burst", instead of always being None.

Why

The SDK read the limit type only from an X-RateLimit-Type header, which the Tango API does not send.
The API names the tripped rate in the 429 body's detail instead: Rate limit exceeded for daily. Please try again in 16 hours, 58 minutes.
This matches tango-python 1.18.2, which reads the same field the same way.

How

• The rate's name after exceeded for is read, never the wait text, so a daily lockout whose wait mentions minutes is not reported as burst.
• Daily is checked first (daily, or the word day), then burst (burst or minute); anything else is None.
• A premium endpoint's per-scope budget (premium_daily) reports as "daily".
• A non-empty X-RateLimit-Type header still takes precedence, so a future header wins.
• No public type changes: the field already existed on Error::RateLimit (the enum is #[non_exhaustive]; no variant or field is added). RateLimitInfo is untouched.

Testing

• Unit tests: the daily message above, daily with a one-minute wait, burst with seconds and minute waits, a burst whose wait mentions a day, premium_daily, Too many requests., an empty detail, a non-string detail, a non-JSON body, an empty body, header precedence, and an empty header falling back to the detail.
• Integration test through the mock server: a daily 429 without the header yields Some("daily").
• cargo fmt --check and cargo clippy --workspace --all-features -- -D warnings on 1.80 and stable; cargo test --workspace with --all-features and --no-default-features on stable and 1.80.

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