Resolve survival/decrement method ambiguities (breaking: narrower first-argument types)

[alecloudenback]

master has 5 ambiguous method pairs (2 on survival, 3 on decrement). Two of them defeat guard rails that exist on purpose: survival(Makeham(), 65, Uniform()) and survival(table, 10, Uniform()) raise an ambiguity MethodError instead of working or raising the intended ArgumentError.

Changes

• The rate-vector survival methods take v::AbstractArray instead of an untyped first argument.
• The integer-age method that took a DeathDistribution and ignored it now delegates to the plain integer method.
• The from_age == to_age special case is gone; reducing over an empty view already returns init, which is also what gives the documented "reversed ages return 1.0" behavior.
• decrement is one method, decrement(v, args...) = 1 - survival(v, args...). Table misuse routes through the survival ArgumentError.
• Parametric models accept and ignore a trailing DeathDistribution (LifeContingencies' SingleLife passes one and currently gets a MethodError), and omega(::ParametricMortality) == Inf.

Testing

• Test.detect_ambiguities is now asserted empty in the suite (0, down from 5).
• length(methods(decrement)) == 1.
• New tests for the ArgumentError on tables with a DeathDistribution, and for the parametric pass-throughs and omega.

---

Stacked on #137 (base branch refactor/02-deps). Merge the stack in order; once the base PR is merged and its branch deleted, GitHub retargets this PR to master.

🤖 Generated with Claude Code

https://claude.ai/code/session_01JFnc6pvofuNXTW2xdCcewT

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
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Additional details and impacted files

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