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, 1 deletions

diff --git a/todo.org b/todo.org
index 06deb72..f9bdf35 100644
--- a/todo.org
+++ b/todo.org
@@ -1124,11 +1124,14 @@ Scope:
 
 Origin: came up while authoring =triage-intake.org= on 2026-05-11; body refreshed after the engine/plugin refactor on 2026-05-26.
 
-** TODO [#C] Templatize =make coverage-summary= into the language bundles :feature:solo:
+** DONE [#C] Templatize =make coverage-summary= into the language bundles (Elisp pilot) :feature:solo:
+CLOSED: [2026-05-31 Sun]
 :PROPERTIES:
 :LAST_REVIEWED: 2026-05-28
 :END:
 
+Done 2026-05-31 (Elisp pilot, the scoped milestone): ported the kernel into the elisp bundle as a self-contained =languages/elisp/claude/scripts/coverage-summary.el= (no coverage-core dependency), proven end-to-end against the real dotemacs SimpleCov report (93 tracked, 27 untested modules surfaced, project number 66.4%). The missing-file-as-0% + unit-weighted number is the kernel. Delivery: the script ships under =.claude/scripts/= (gitignored, auto-fixed on drift by =sync-language-bundle.sh=); =languages/elisp/coverage-makefile.txt= holds the project-owned Makefile fragment, seeded at project root by =install-lang.sh= and dropped into =.ai/inbox/= by sync when that convention exists. Tests: 12 ERT (=languages/elisp/tests/=, wired into =make test=), 5 new sync bats, 2 new install-lang bats. The fan-out to Python/Go/TS is the follow-up below.
+
 Borrow dotemacs's =make coverage-summary= into the language bundles. After =make coverage= writes a coverage file, =coverage-summary= prints per-unit covered/total with percentages, a unit-weighted project number, and a list of source files present on disk but missing from the coverage report.
 
 *The kernel — the only part worth building.* Weight the project number by file/module rather than by line, and count a source file absent from the report as 0% instead of omitting it. A module no test imports just doesn't appear in coverage.py or nyc output, so it silently fails to drag the number down. That missing-file detection is the value; everything else (per-file table, total) the built-in reporters already print, so don't reimplement those.
@@ -1153,6 +1156,19 @@ Reference (dotemacs): =scripts/coverage-summary.el=, =modules/coverage-core.el=,
 
 Origin: handoff from the .emacs.d session, 2026-05-25.
 
+** TODO [#C] Fan out coverage-summary to Python, Go, and TypeScript bundles :feature:
+:PROPERTIES:
+:CREATED: [2026-05-31 Sun]
+:END:
+
+The Elisp pilot proved the pattern (see the DONE task above). Each remaining bundle needs its own ~40-line parser over that tool's report format, plus a =coverage-makefile.txt= fragment and the prereq harness where one is missing. The bundle plumbing is already generic: =sync-language-bundle.sh= auto-fixes any =claude/scripts/*= and inbox-drops any =coverage-makefile.txt=; =install-lang.sh= seeds the fragment; =make test= discovers =languages/*/tests/test-*.el=. So each language is just: the parser script, its tests, and the fragment.
+
+- Python: =coverage json= per-file JSON, or lean on =coverage report=. Missing-file detection over the package's =*.py= on disk.
+- Go: =go test -coverprofile=cover.out=; parse =cover.out= (simple text), or =go tool cover -func=.
+- TypeScript/JS: nyc/Istanbul =coverage-final.json= / json-summary.
+
+Keep the kernel identical: file-weighted project number, source files absent from the report counted as 0%. Don't reimplement the per-file table where the built-in reporter already prints one — Python and JS both do, so those scripts can focus on the missing-file list and the project number.
+
 ** TODO [#B] Cross-project pattern catalog :spec:thinking:
 :PROPERTIES:
 :LAST_REVIEWED: 2026-05-28