Document curve API constraints and troubleshooting

[uriahf]

What changed

• adds a focused Curve API Compatibility guide covering shared population conventions and the remaining time-dependent differences
• adds a Common Errors & Fixes guide keyed by literal exception text
• documents the supported matching-key multi-population contract introduced by Fix calibration multi-population input contract #291
• documents integer fixed_time_horizons support introduced by Normalize integer fixed time horizons #292
• documents the targeted unsupported-calibration-heuristics error introduced by Raise actionable errors for unsupported calibration heuristics #293
• clarifies when censoring and competing-event heuristics are statistically irrelevant because the corresponding outcome type is absent
• enables Great Docs' GitHub-release-backed changelog
• adds a curated skills/rtichoke/SKILL.md so Great Docs can publish package-specific agent guidance alongside llms.txt / llms-full.txt

Why

Recent integration work exposed several places where similarly named rtichoke functions have different behavioral contracts. The docs should emphasize the conventions the curve families share and make the real remaining asymmetries discoverable without overstating differences.

After #291, matching-key Train/Test populations may have different sample sizes. After #292, integer and floating-point fixed time horizons are equivalent. After #293, unsupported calibration heuristics fail early with an actionable error. The main remaining API asymmetry documented here is that create_calibration_curve_times() requires an explicit heuristics_sets argument and accepts a narrower set of heuristics than its sibling curve families.

Great Docs integration

The new user-guide pages flow into llms-full.txt; the curated skill captures high-value gotchas in a compact agent-oriented form; and the changelog is sourced from GitHub Releases rather than maintained as duplicate history.

Scope

Documentation only. This PR does not change calibration defaults or statistical behavior.

[github-actions]

PR Preview Action v1.8.1
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2026-08-12 06:56 UTC