[alexanderdibenedetto]

Remove:
kTSKPublicKeyAlgorithms, TSKSupportedAlgorithm and the kTSKAlgorithm*
constants have been deprecated since 1.6.0. Configs that still set
TSKPublicKeyAlgorithms keep working because the parser ignores unknown keys.

Also delete the unused internal TSKPublicKeyAlgorithm.h and rename
TSKPublicKeyAlgorithmTests to TSKSPKIHashCacheTests, after the class it tests.

[claude]

I reviewed this PR and didn't find any bugs. It removes exported public symbols, though, so any client that still references them will stop compiling. A maintainer should confirm this goes into a release that's allowed to break source compatibility.

What was reviewed:

• Searched for leftover references to kTSKPublicKeyAlgorithms, TSKSupportedAlgorithm, the kTSKAlgorithm* constants and TSKPublicKeyAlgorithm outside docs/. There are none in sources, tests, Package.swift or the project file.
• Checked that configs which still set TSKPublicKeyAlgorithms keep working. parse_configuration.m looks up each known key by name, so an extra key is ignored. The only exception is a domain with TSKExcludeSubdomainFromParentPolicy set, which already rejected this key before the change.
• Checked the test rename in all five test targets in the pbxproj (file reference IDs are kept), and the NUL-safe existing() filter in scripts/lint.sh.
• The generated HTML in docs/documentation still lists the removed symbols until it is regenerated.

Extended reasoning...

The change deletes deprecated public constants and a typedef from TSKTrustKitConfig.h/.m, removes an unused internal header, renames a test file, and filters deleted paths out of lint.sh. It touches no runtime pinning or crypto logic: SPKI hashing and validation are unchanged, and the parser never read the removed key. The code is mechanical and consistent across the project file. I deferred because removing exported symbols breaks the public API for downstream clients, and whether to do that now is a versioning call for a maintainer.