Add --summary flag support to coverage script

Add --summary flag to hide detailed test output and coverage tables,
showing only the final coverage summary. Add console.log blank line
after header for consistent formatting. Change header text from
"Running Coverage" to "Test Coverage" for consistency. Filter custom
flags from vitest arguments to prevent unknown option errors.

Author: jdalton

scripts/cover.mjs

@@ -11,6 +11,7 @@
  *   --open       Open coverage report in browser
  *   --code-only  Run only code coverage (skip type coverage)
  *   --type-only  Run only type coverage (skip code coverage)
+ *   --summary    Show only coverage summary (hide detailed output)
  */
 
 import { parseArgs } from 'node:util'
@@ -53,17 +54,27 @@ async function main() {
     options: {
       'code-only': { type: 'boolean', default: false },
       'type-only': { type: 'boolean', default: false },
+      summary: { type: 'boolean', default: false },
     },
     strict: false,
   })
 
   try {
     if (!quiet) {
-      printHeader('Running Coverage')
+      printHeader('Test Coverage')
+      console.log('')
     }
 
     // Run vitest with coverage enabled, capturing output
-    const vitestArgs = ['exec', 'vitest', 'run', '--coverage']
+    // Filter out custom flags that vitest doesn't understand
+    const customFlags = ['--code-only', '--type-only', '--summary']
+    const vitestArgs = [
+      'exec',
+      'vitest',
+      'run',
+      '--coverage',
+      ...process.argv.slice(2).filter(arg => !customFlags.includes(arg)),
+    ]
     const typeCoverageArgs = ['exec', 'type-coverage']
 
     let exitCode = 0
@@ -95,9 +106,13 @@ async function main() {
       }
 
       if (exitCode === 0) {
-        if (!quiet) {printSuccess('Coverage completed successfully')}
+        if (!quiet) {
+          printSuccess('Coverage completed successfully')
+        }
       } else {
-        if (!quiet) {printError('Coverage failed')}
+        if (!quiet) {
+          printError('Coverage failed')
+        }
         process.exitCode = 1
       }
       return
@@ -123,7 +138,7 @@ async function main() {
         const testSummaryMatch = output.match(
           /Test Files\s+\d+[^\n]*\n[\s\S]*?Duration\s+[\d.]+m?s[^\n]*/,
         )
-        if (testSummaryMatch) {
+        if (!values.summary && testSummaryMatch) {
           console.log()
           console.log(testSummaryMatch[0])
           console.log()
@@ -138,13 +153,15 @@ async function main() {
         )
 
         if (coverageHeaderMatch && allFilesMatch) {
-          console.log(' % Coverage report from v8')
-          console.log(coverageHeaderMatch[1])
-          console.log(coverageHeaderMatch[2])
-          console.log(coverageHeaderMatch[1])
-          console.log(allFilesMatch[0])
-          console.log(coverageHeaderMatch[1])
-          console.log()
+          if (!values.summary) {
+            console.log(' % Coverage report from v8')
+            console.log(coverageHeaderMatch[1])
+            console.log(coverageHeaderMatch[2])
+            console.log(coverageHeaderMatch[1])
+            console.log(allFilesMatch[0])
+            console.log(coverageHeaderMatch[1])
+            console.log()
+          }
 
           const codeCoveragePercent = Number.parseFloat(allFilesMatch[1])
           console.log(' Coverage Summary')
@@ -158,9 +175,13 @@ async function main() {
       }
 
       if (exitCode === 0) {
-        if (!quiet) {printSuccess('Coverage completed successfully')}
+        if (!quiet) {
+          printSuccess('Coverage completed successfully')
+        }
       } else {
-        if (!quiet) {printError('Coverage failed')}
+        if (!quiet) {
+          printError('Coverage failed')
+        }
         process.exitCode = 1
       }
       return
@@ -202,20 +223,22 @@ async function main() {
 
     // Display clean output
     if (!quiet) {
-      if (testSummaryMatch) {
+      if (!values.summary && testSummaryMatch) {
         console.log()
         console.log(testSummaryMatch[0])
         console.log()
       }
 
       if (coverageHeaderMatch && allFilesMatch) {
-        console.log(' % Coverage report from v8')
-        console.log(coverageHeaderMatch[1]) // Top border
-        console.log(coverageHeaderMatch[2]) // Header row
-        console.log(coverageHeaderMatch[1]) // Middle border
-        console.log(allFilesMatch[0]) // All files row
-        console.log(coverageHeaderMatch[1]) // Bottom border
-        console.log()
+        if (!values.summary) {
+          console.log(' % Coverage report from v8')
+          console.log(coverageHeaderMatch[1]) // Top border
+          console.log(coverageHeaderMatch[2]) // Header row
+          console.log(coverageHeaderMatch[1]) // Middle border
+          console.log(allFilesMatch[0]) // All files row
+          console.log(coverageHeaderMatch[1]) // Bottom border
+          console.log()
+        }
 
         // Display type coverage and cumulative summary
         if (typeCoverageMatch) {