feat(kyberforge): retarget skill-author to author into .apm/skills/

Skills now migrate from hand-authored plugin.json to Microsoft APM
(apm.yml + .apm/) per ADR-0015/issue #89. skill-author's write location
switches accordingly: walk up from the destination to the nearest
ancestor apm.yml declaring a type: field (skipping type:-less
marketplace-only manifests) and scaffold into <package-root>/.apm/skills/
<name>/. Standalone authoring (no apm.yml/.git anywhere, e.g.
~/.agents/skills/) is unchanged — only the old plugin.json-based path is
replaced, not standalone mode.

Refs: #89

plugins/kyberforge/skills/skill-author/tests/new-skill.bats

@@ -117,3 +117,70 @@ teardown() {
     assert_success
     assert_output --partial "nothing to do"
 }
+
+# ---------------------------------------------------------------------------
+# Mode detection: package vs standalone
+# ---------------------------------------------------------------------------
+
+@test "standalone mode is chosen when no apm.yml or .git is found above path" {
+    run bash "$SCRIPT" my-tool "$DEST"
+    assert_success
+    assert_output --partial "Mode: standalone"
+    assert [ -d "$DEST/my-tool" ]
+}
+
+@test "package mode: writes into <package-root>/.apm/skills/<name>, not under the given subdir" {
+    mkdir -p "$DEST/pkg/sub/deep"
+    cat > "$DEST/pkg/apm.yml" <<'EOF'
+name: my-pkg
+version: 1.0.0
+type: skill
+EOF
+    run bash "$SCRIPT" my-tool "$DEST/pkg/sub/deep"
+    assert_success
+    assert_output --partial "Mode: package"
+    assert [ -d "$DEST/pkg/.apm/skills/my-tool" ]
+    assert [ ! -d "$DEST/pkg/sub/deep/my-tool" ]
+}
+
+@test "package mode scaffold contains SKILL.md with name substituted" {
+    mkdir -p "$DEST/pkg"
+    cat > "$DEST/pkg/apm.yml" <<'EOF'
+name: my-pkg
+version: 1.0.0
+type: hybrid
+EOF
+    bash "$SCRIPT" my-tool "$DEST/pkg"
+    assert [ -f "$DEST/pkg/.apm/skills/my-tool/SKILL.md" ]
+    run grep "my-tool" "$DEST/pkg/.apm/skills/my-tool/SKILL.md"
+    assert_success
+}
+
+@test "walk-up skips a type-less apm.yml (marketplace-only) and finds a real package root further up" {
+    mkdir -p "$DEST/mid/sub"
+    cat > "$DEST/apm.yml" <<'EOF'
+name: root-pkg
+version: 1.0.0
+type: skill
+EOF
+    cat > "$DEST/mid/apm.yml" <<'EOF'
+marketplace:
+  owner: acme
+  packages: []
+EOF
+    run bash "$SCRIPT" my-tool "$DEST/mid/sub"
+    assert_success
+    assert_output --partial "Mode: package"
+    assert [ -d "$DEST/.apm/skills/my-tool" ]
+    assert [ ! -d "$DEST/mid/.apm" ]
+}
+
+@test "walk-up stops at .git boundary and uses standalone mode at the given path" {
+    mkdir -p "$DEST/repo/.git"
+    mkdir -p "$DEST/repo/sub"
+    run bash "$SCRIPT" my-tool "$DEST/repo/sub"
+    assert_success
+    assert_output --partial "Mode: standalone"
+    assert [ -d "$DEST/repo/sub/my-tool" ]
+    assert [ ! -d "$DEST/repo/my-tool" ]
+}