Change TRACY_ENABLE default to OFF to match documentation.

The documentation states that Tracy is disabled by default, but the
build system defaults were ON/true. Change CMake and Meson defaults to
OFF/false. Projects that need profiling enabled must now opt in
explicitly. Add explicit TRACY_ENABLE=ON / tracy_enable=true to CI
steps and the test project to preserve existing behavior.

.github/workflows/linux.yml

@@ -56,14 +56,14 @@ jobs:
         cmake --build merge/build --parallel
     - name: Library (cmake)
       run: |
-        cmake -B build -DCMAKE_BUILD_TYPE=Release
+        cmake -B build -DCMAKE_BUILD_TYPE=Release -DTRACY_ENABLE=ON
         cmake --build build
         cmake --install build
       env:
         CMAKE_INSTALL_PREFIX: ${{ github.workspace }}/bin
     - name: Library (meson)
       run: |
-        meson setup -Dprefix=$GITHUB_WORKSPACE/bin/lib build-meson
+        meson setup -Dprefix=$GITHUB_WORKSPACE/bin/lib -Dtracy_enable=true build-meson
         meson compile -C build-meson
     - name: Test application
       run: |

.github/workflows/macos.yml

@@ -50,7 +50,7 @@ jobs:
         cmake -B merge/build -S merge -DCMAKE_BUILD_TYPE=Release -DGIT_REV=${{ github.sha }}
         cmake --build merge/build --parallel --config Release
     - name: Build library
-      run: meson setup -Dprefix=$GITHUB_WORKSPACE/bin/lib build && meson compile -C build && meson install -C build
+      run: meson setup -Dprefix=$GITHUB_WORKSPACE/bin/lib -Dtracy_enable=true build && meson compile -C build && meson install -C build
     - name: Package artifacts
       run: |
         mkdir -p bin

.github/workflows/mingw.yml

@@ -30,7 +30,7 @@ jobs:
         restore-keys: ${{ runner.os }}-cpm-
     - name: Build TracyClient
       run: |
-        cmake -B build -DCMAKE_BUILD_TYPE=Release \
+        cmake -B build -DCMAKE_BUILD_TYPE=Release -DTRACY_ENABLE=ON \
           -DCMAKE_SYSTEM_NAME=Windows \
           -DCMAKE_C_COMPILER=x86_64-w64-mingw32-gcc \
           -DCMAKE_CXX_COMPILER=x86_64-w64-mingw32-g++
@@ -50,7 +50,7 @@ jobs:
         cpu = 'x86_64'
         endian = 'little'
         EOF
-        meson setup build-meson --cross-file mingw-cross.txt -Ddefault_library=static
+        meson setup build-meson --cross-file mingw-cross.txt -Ddefault_library=static -Dtracy_enable=true
         meson compile -C build-meson
     - name: Test application
       run: |