Rename reset_defaults! to make_preferences_dynamic!

Renamed the function to better reflect its purpose:
- **Old name**: reset_defaults!()
- **New name**: make_preferences_dynamic!()
- **Better naming**: Clearly indicates it makes preferences dynamic for testing
- **Updated**: Test file and documentation to use new name

The new name better describes what the function does - it makes the
preference system dynamic by switching from compile-time constants
to runtime preference checking for testing verification.

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <[email protected]>

Author: ChrisRackauckas

docs/src/advanced/internal_api.md

@@ -33,7 +33,7 @@ LinearSolve.defaultalg
 LinearSolve.get_tuned_algorithm
 LinearSolve.is_algorithm_available
 LinearSolve.show_algorithm_choices
-LinearSolve.reset_defaults!
+LinearSolve.make_preferences_dynamic!
 ```
 
 ### Preference System Internals

src/preferences.jl

@@ -143,21 +143,19 @@ const AUTOTUNE_PREFS_SET = let
     any_set
 end
 
-# Testing mode flag
-const TESTING_MODE = Ref(false)
 
 """
-    reset_defaults!()
+    make_preferences_dynamic!()
 
-**Internal function for testing only.** Enables testing mode where preferences
-are checked at runtime instead of using compile-time constants. This allows
-tests to verify that the preference system works correctly.
+**Internal function for testing only.** Makes preferences dynamic by redefining
+get_tuned_algorithm to check preferences at runtime instead of using compile-time
+constants. This allows tests to verify that the preference system works correctly.
 
 !!! warning "Testing Only"
     This function is only intended for internal testing purposes. It modifies
     global state and should never be used in production code.
 """
-function reset_defaults!()
+function make_preferences_dynamic!()
     # Redefine get_tuned_algorithm to use runtime preference checking for testing
     @eval function get_tuned_algorithm(::Type{eltype_A}, ::Type{eltype_b}, matrix_size::Integer) where {eltype_A, eltype_b}
         # Determine the element type to use for preference lookup

test/preferences.jl

@@ -2,8 +2,8 @@ using LinearSolve, LinearAlgebra, Test
 using Preferences
 
 @testset "Dual Preference System Integration Tests" begin
-    # Enable testing mode for preference system verification
-    LinearSolve.reset_defaults!()
+    # Make preferences dynamic for testing verification
+    LinearSolve.make_preferences_dynamic!()
 
     # Clear any existing preferences to start clean
     target_eltypes = ["Float32", "Float64", "ComplexF32", "ComplexF64"]