fix: fresh user test — xlings remove + replace with self-hosted binary

Replace the xlings-installed mcpp with the self-hosted build, then
test the exact user flow:
  mcpp new hello
  cd hello
  mcpp run

Uses `mcpp` from PATH (like a real user), but the binary is the
current code (not the old 0.0.17 release).

Author: Sunrisepeak

.github/workflows/ci-macos.yml

@@ -316,12 +316,18 @@ jobs:
           "$MCPP" --version
           echo ":: Self-host smoke PASS"
 
-      - name: Fresh user experience (mcpp new → run)
+      - name: Fresh user experience (xlings install mcpp → new → run)
         run: |
-          MCPP=$(find target -path "*/bin/mcpp" | head -1)
-          MCPP=$(cd "$(dirname "$MCPP")" && pwd)/$(basename "$MCPP")
+          # Replace xlings mcpp with our self-hosted build
+          MCPP_SELF=$(find target -path "*/bin/mcpp" | head -1)
+          MCPP_SELF=$(cd "$(dirname "$MCPP_SELF")" && pwd)/$(basename "$MCPP_SELF")
+          xlings remove mcpp -y 2>/dev/null || true
+          MCPP_BIN=$(which mcpp 2>/dev/null || echo "$HOME/.xlings/subos/default/bin/mcpp")
+          cp "$MCPP_SELF" "$MCPP_BIN"
+          chmod +x "$MCPP_BIN"
+
           TMP=$(mktemp -d)
           cd "$TMP"
-          "$MCPP" new hello
+          mcpp new hello
           cd hello
-          "$MCPP" run
+          mcpp run

.github/workflows/ci-windows.yml

@@ -108,16 +108,20 @@ jobs:
           "$MCPP_SELF" --version
           echo ":: Self-host smoke PASS"
 
-      - name: Fresh user experience (mcpp new → run)
+      - name: Fresh user experience (xlings install mcpp → new → run)
         shell: bash
         run: |
-          # Use the self-hosted binary (current code with all fixes).
-          # This simulates: user installs mcpp → mcpp new hello → mcpp run
+          # Replace xlings mcpp with our self-hosted build, then test
+          # the real user flow: mcpp new hello && cd hello && mcpp run
+          xlings.exe remove mcpp -y 2>/dev/null || true
+          MCPP_BIN=$(which mcpp.exe 2>/dev/null || echo "$USERPROFILE/.xlings/subos/default/bin/mcpp.exe")
+          cp "$MCPP_SELF" "$MCPP_BIN"
+
           TMP=$(mktemp -d)
           cd "$TMP"
-          "$MCPP_SELF" new hello
+          mcpp.exe new hello
           cd hello
-          "$MCPP_SELF" run
+          mcpp.exe run
 
       - name: Package Windows release zip
         id: package

.github/workflows/ci.yml

@@ -134,11 +134,17 @@ jobs:
           "$MCPP" build
           "$MCPP" test
 
-      - name: Fresh user experience (mcpp new → run)
+      - name: Fresh user experience (xlings install mcpp → new → run)
         run: |
-          MCPP=$(realpath "$(find target -type f -name mcpp -printf '%T@ %p\n' | sort -rn | head -1 | cut -d' ' -f2)")
+          # Replace xlings mcpp with our self-hosted build
+          MCPP_SELF=$(realpath "$(find target -type f -name mcpp -printf '%T@ %p\n' | sort -rn | head -1 | cut -d' ' -f2)")
+          xlings remove mcpp -y 2>/dev/null || true
+          MCPP_BIN=$(which mcpp 2>/dev/null || echo "$HOME/.xlings/subos/default/bin/mcpp")
+          cp "$MCPP_SELF" "$MCPP_BIN"
+          chmod +x "$MCPP_BIN"
+
           TMP=$(mktemp -d)
           cd "$TMP"
-          "$MCPP" new hello
+          mcpp new hello
           cd hello
-          "$MCPP" run
+          mcpp run