[patch] Keep NormalizedParameter.Normalize in [0, 1] for out-of-domain values and reject empty ranges

[matt-edmondson]

Fixes #319

What changed

NormalizedParameter<T>.Normalize relied on Math.Clamp, which passes NaN straight through. The result:

• Logarithmic(20, 20000).Normalize(-5) returned NaN for double
• the decimal version threw OverflowException
• a zero-width Linear(1, 1) produced NaN as well

Changes:

• Logarithmic taper: a value at zero, or on the other side of zero from the range, now maps to the nearer end, meaning the end with the smaller magnitude. That is 0 for 20..20000, and 1 for a falling 20000..20 range.
• NaN guard: a NaN shaped value maps to 0 before clamping, so the host always gets a position in [0, 1].
• Construction: Linear, Skewed and Logarithmic reject min == max with ArgumentOutOfRangeException, as the triage suggested, so the misconfiguration shows up where it is made. WithCenter already rejected it. No caller in the repository builds a zero-width range.

Tests

The four new tests in AudioEngineeringTests all failed before the fix and pass after it:

• log values at or below zero, on rising, falling and negative ranges
• the decimal overflow case
• NaN input
• zero-width ranges for each factory

Full Semantics.Test on net10.0: 1484 passed, 8 skipped, 0 failed. The local Sonar build (.sonarlint/sonar-local.props) reports nothing on the changed file.

🤖 Generated with Claude Code

https://claude.ai/code/session_01A5MkmzQ4qxxRmHStdQ8oJA

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[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
100.0% Coverage on New Code
0.0% Duplication on New Code

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