feat(elisp): add coverage-summary to the Elisp bundle with missing-file detection

A line-weighted coverage total has a blind spot: a module no test loads never shows up in the SimpleCov report, so it can't drag the number down. The suite looks healthier than it is. This adds a summary that counts every source file on disk against the report and treats an absent file as 0%, weighting the project number by file instead of by line so untested modules stay visible.

The script ships at languages/elisp/claude/scripts/coverage-summary.el, self-contained on stock Emacs (just the built-in json). It parses the undercover SimpleCov shape directly rather than depending on the editor's coverage engine, so it runs anywhere the bundle lands. I proved it against a real 103-file report: 93 tracked, 27 untested modules surfaced, project number 66.4%.

Delivery follows the bundle convention. The script lives under the gitignored .claude/ footprint and gets auto-fixed on drift by sync-language-bundle.sh, which I made generic for any claude/scripts/* rather than coverage-specific. The Makefile targets ship as a project-owned fragment (languages/elisp/coverage-makefile.txt) that install-lang.sh seeds at the project root and sync drops into .ai/inbox/ when that convention exists. The bundle never edits the project's own Makefile.

Tests: 12 ERT for the kernel (Normal/Boundary/Error per function), wired into make test via a new languages/*/tests/ discovery path, plus bats for the sync auto-fix and the inbox-drop guards.

This is the Elisp pilot. The pattern is proven, so fanning out to Python, Go, and TypeScript is now a follow-up. Each one needs only its own parser and fragment. The plumbing is already generic.

1 files changed, 17 insertions, 0 deletions

diff --git a/scripts/tests/install-lang.bats b/scripts/tests/install-lang.bats
index 523be99..a26c3d5 100644
--- a/scripts/tests/install-lang.bats
+++ b/scripts/tests/install-lang.bats
@@ -25,6 +25,23 @@ teardown() {
   [ -d "$PROJECT/.claude/rules" ]
   [ -d "$PROJECT/githooks" ]
   [ -f "$PROJECT/CLAUDE.md" ]
+  # The coverage-summary script ships inside the gitignored .claude footprint.
+  [ -f "$PROJECT/.claude/scripts/coverage-summary.el" ]
+}
+
+@test "install-lang elisp: seeds the project-owned coverage Makefile fragment" {
+  run bash "$INSTALL_LANG" elisp "$PROJECT"
+
+  [ "$status" -eq 0 ]
+  [ -f "$PROJECT/coverage-makefile.txt" ]
+}
+
+@test "install-lang elisp: does not overwrite an existing fragment without FORCE" {
+  echo "MY OWN VERSION" > "$PROJECT/coverage-makefile.txt"
+  run bash "$INSTALL_LANG" elisp "$PROJECT"
+
+  [ "$status" -eq 0 ]
+  grep -qxF "MY OWN VERSION" "$PROJECT/coverage-makefile.txt"
 }
 
 @test "install-lang elisp: gitignores the full Claude tooling footprint" {