Retry strategies

Built-ins (all return a StrategyFn):

• decorrelated_jitter(base_s=0.25, max_s=30.0) – sleeps uniformly in [base_s, prev_sleep*3], clamped to max_s.
• equal_jitter(base_s=0.25, max_s=30.0) – exponential with jitter in [cap/2, cap], cap = min(max_s, base_s*2^attempt).
• token_backoff(base_s=0.25, max_s=20.0) – gentler exponential (1.5^attempt) with jitter.

Example:

from redress import RetryPolicy, default_classifier
from redress.errors import ErrorClass
from redress.strategies import decorrelated_jitter, equal_jitter

policy = RetryPolicy(
    classifier=default_classifier,
    strategy=decorrelated_jitter(max_s=10.0),  # default for most classes
    strategies={
        ErrorClass.RATE_LIMIT: decorrelated_jitter(max_s=60.0),
        ErrorClass.SERVER_ERROR: equal_jitter(max_s=30.0),
    },
)