test: add run-tests.sh, fix stale tests for marketplace model

- Add tests/run-tests.sh: discovers and runs all test-*.sh (including
  plugin subdirs) and the bats suite; replaces per-script pre-push calls
- Add tests/run-tests.bats: TDD coverage for run-tests.sh behaviours
- Update setup-hooks.sh: pre-push block now calls run-tests.sh
- Fix test-install.sh: remove provider adapter symlink tests (adapter
  removed in marketplace migration), guard skills loops on dir existence
- Fix test-instructions-and-docs.sh: content index checks now point to
  core/AGENTS.md (where it lives), remove ard/bug dir assertions
- Fix test-setup-hooks.sh: assert pre-push hook calls run-tests.sh

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

tests/run-tests.bats

@@ -0,0 +1,66 @@
+#!/usr/bin/env bats
+
+REPO_ROOT="$(cd "$(dirname "$BATS_TEST_FILENAME")/.." && pwd)"
+RUN_TESTS="$REPO_ROOT/tests/run-tests.sh"
+
+setup() {
+  SCRATCH="$(mktemp -d)"
+}
+
+teardown() {
+  rm -rf "$SCRATCH"
+}
+
+# --- Tracer bullet ---
+
+@test "exits 0 when all test scripts pass" {
+  mkdir -p "$SCRATCH/tests"
+  printf '#!/usr/bin/env bash\necho "ok"\n' > "$SCRATCH/tests/test-one.sh"
+  chmod +x "$SCRATCH/tests/test-one.sh"
+  TEST_DIR="$SCRATCH" run bash "$RUN_TESTS"
+  [ "$status" -eq 0 ]
+}
+
+# --- Failure detection ---
+
+@test "exits non-zero when a test script fails" {
+  mkdir -p "$SCRATCH/tests"
+  printf '#!/usr/bin/env bash\nexit 1\n' > "$SCRATCH/tests/test-bad.sh"
+  chmod +x "$SCRATCH/tests/test-bad.sh"
+  TEST_DIR="$SCRATCH" run bash "$RUN_TESTS"
+  [ "$status" -ne 0 ]
+}
+
+@test "reports the name of the failing script" {
+  mkdir -p "$SCRATCH/tests"
+  printf '#!/usr/bin/env bash\nexit 1\n' > "$SCRATCH/tests/test-bad.sh"
+  chmod +x "$SCRATCH/tests/test-bad.sh"
+  TEST_DIR="$SCRATCH" run bash "$RUN_TESTS"
+  [[ "$output" == *"test-bad.sh"* ]]
+}
+
+# --- Subdirectory discovery ---
+
+@test "discovers test scripts in subdirectories" {
+  mkdir -p "$SCRATCH/plugins/myplugin"
+  printf '#!/usr/bin/env bash\necho "plugin test ok"\n' > "$SCRATCH/plugins/myplugin/test-plugin.sh"
+  chmod +x "$SCRATCH/plugins/myplugin/test-plugin.sh"
+  TEST_DIR="$SCRATCH" run bash "$RUN_TESTS"
+  [ "$status" -eq 0 ]
+  [[ "$output" == *"test-plugin.sh"* ]]
+}
+
+@test "does not pick up scripts not named test-*.sh" {
+  mkdir -p "$SCRATCH/tests"
+  printf '#!/usr/bin/env bash\nexit 1\n' > "$SCRATCH/tests/run-bats.sh"
+  chmod +x "$SCRATCH/tests/run-bats.sh"
+  TEST_DIR="$SCRATCH" run bash "$RUN_TESTS"
+  [ "$status" -eq 0 ]
+}
+
+# --- Bats integration ---
+
+@test "runs the bats suite when no TEST_DIR override is set" {
+  run bash "$RUN_TESTS" --bats-only
+  [ "$status" -eq 0 ]
+}