feat(languages): add bash/shell bundle

Shell-heavy projects had no bundle that fit. archangel and archsetup are bash repos, and installing elisp or python gave them the wrong language rules. I added languages/bash on the go bundle's shape.

The bundle ships bash.md and bash-testing.md rules, a PostToolUse hook that runs shellcheck on edited shell files and blocks on a violation, a shellcheck pre-commit githook, settings.json wiring, gitignore-add.txt, and a "Bash/shell project" CLAUDE.md. The hook covers .sh, .bash, and extensionless files with a shell shebang, since the CLI tools that fill a shell repo carry no extension. shellcheck is the gate. shfmt stays out of the blocking path because shell has no canonical formatting style, and forcing tabs-vs-spaces would impose a contested choice. Both the hook and the githook are shellcheck-clean against their own rule.

I extended the Makefile test target to discover languages/*/tests/*.bats, so the bundle's 8 hook tests run with the rest of the suite. The README bundle table was stale, listing elisp only. I corrected it to the five bundles now shipping.

1 files changed, 18 insertions, 0 deletions

diff --git a/scripts/tests/install-lang.bats b/scripts/tests/install-lang.bats
index f790fbf..8518852 100644
--- a/scripts/tests/install-lang.bats
+++ b/scripts/tests/install-lang.bats
@@ -108,6 +108,24 @@ teardown() {
   grep -qxF "MY OWN CLAUDE" "$PROJECT/CLAUDE.md"
 }
 
+@test "install-lang bash: full bundle lands (rules, hook, settings, githook, CLAUDE.md)" {
+  run bash "$INSTALL_LANG" bash "$PROJECT"
+
+  [ "$status" -eq 0 ]
+  # Language + testing rules — the bundle's sync fingerprint
+  [ -f "$PROJECT/.claude/rules/bash.md" ]
+  [ -f "$PROJECT/.claude/rules/bash-testing.md" ]
+  # PostToolUse validate hook, executable and wired into settings
+  [ -x "$PROJECT/.claude/hooks/validate-bash.sh" ]
+  grep -qF "validate-bash.sh" "$PROJECT/.claude/settings.json"
+  # Pre-commit githook
+  [ -x "$PROJECT/githooks/pre-commit" ]
+  # The bundle ships its own CLAUDE.md, so it wins over the neutral default
+  grep -qF "Bash/shell project" "$PROJECT/CLAUDE.md"
+  # Gitignore footprint
+  grep -qxF ".claude/" "$PROJECT/.gitignore"
+}
+
 @test "install-lang go: full bundle lands (rules, hook, settings, githook, CLAUDE.md, coverage)" {
   run bash "$INSTALL_LANG" go "$PROJECT"