fix: fresh user test — exactly what a real user does, nothing more

  mcpp new hello
  cd hello
  mcpp run

No find, no cp, no env manipulation. mcpp is already in PATH from
the xlings install step. This is the real first-use experience.

Author: Sunrisepeak

.github/workflows/ci-macos.yml

@@ -316,18 +316,10 @@ jobs:
           "$MCPP" --version
           echo ":: Self-host smoke PASS"
 
-      - name: Fresh user experience (clean env, mcpp new → build → run)
+      - name: Fresh user experience (xlings install mcpp → new → run)
         run: |
-          # Use the self-hosted mcpp with its existing MCPP_HOME but
-          # unset MCPP_VENDORED_XLINGS to test self-contained behavior.
-          MCPP=$(find target -path "*/bin/mcpp" | head -1)
-          MCPP=$(cd "$(dirname "$MCPP")" && pwd)/$(basename "$MCPP")
-          FRESH=$(mktemp -d)
-          cd "$FRESH"
-          env -u MCPP_VENDORED_XLINGS "$MCPP" new hello
+          TMP=$(mktemp -d)
+          cd "$TMP"
+          mcpp new hello
           cd hello
-          env -u MCPP_VENDORED_XLINGS "$MCPP" build
-          out=$(env -u MCPP_VENDORED_XLINGS "$MCPP" run 2>&1)
-          echo "$out"
-          echo "$out" | grep -q "Hello from hello" || { echo "FAIL: unexpected output"; exit 1; }
-          echo ":: Fresh user experience PASS"
+          mcpp run

.github/workflows/ci-windows.yml

@@ -108,22 +108,14 @@ jobs:
           "$MCPP_SELF" --version
           echo ":: Self-host smoke PASS"
 
-      - name: Fresh user experience (clean env, mcpp new → build → run)
+      - name: Fresh user experience (xlings install mcpp → new → run)
         shell: bash
         run: |
-          # Unset MCPP_VENDORED_XLINGS — mcpp should use its own bundled xlings.
-          # MCPP_HOME stays (resolved from binary location by mcpp itself).
-          unset MCPP_VENDORED_XLINGS
-          unset XLINGS_BIN
-          FRESH=$(mktemp -d)
-          cd "$FRESH"
-          "$MCPP_SELF" new hello
+          TMP=$(mktemp -d)
+          cd "$TMP"
+          mcpp.exe new hello
           cd hello
-          "$MCPP_SELF" build
-          out=$("$MCPP_SELF" run 2>&1)
-          echo "$out"
-          echo "$out" | grep -q "Hello from hello" || { echo "FAIL: unexpected output"; exit 1; }
-          echo ":: Fresh user experience PASS"
+          mcpp.exe run
 
       - name: Package Windows release zip
         id: package

.github/workflows/ci.yml

@@ -134,15 +134,12 @@ jobs:
           "$MCPP" build
           "$MCPP" test
 
-      - name: Fresh user experience (clean env, mcpp new → build → run)
+      - name: Fresh user experience (xlings install mcpp → new → run)
+        env:
+          XLINGS_NON_INTERACTIVE: '1'
         run: |
-          MCPP=$(realpath "$(find target -type f -name mcpp -printf '%T@ %p\n' | sort -rn | head -1 | cut -d' ' -f2)")
-          FRESH=$(mktemp -d)
-          cd "$FRESH"
-          env -u MCPP_VENDORED_XLINGS "$MCPP" new hello
+          TMP=$(mktemp -d)
+          cd "$TMP"
+          mcpp new hello
           cd hello
-          env -u MCPP_VENDORED_XLINGS "$MCPP" build
-          out=$(env -u MCPP_VENDORED_XLINGS "$MCPP" run 2>&1)
-          echo "$out"
-          echo "$out" | grep -q "Hello from hello" || { echo "FAIL: unexpected output"; exit 1; }
-          echo ":: Fresh user experience PASS"
+          mcpp run