fix(emception): P0'+P4+P5 — kill stale CDN fallback, LGWIN=24, sort tar entries

P0': stage-core-cdn.mjs now throws immediately if build/cdn is absent
instead of silently falling back to public/cdn or packages/core/cdn.
Stale fallback was root cause of v3.5.0 publishing at 164 MB despite
local npm pack measuring 149.9 MB.

P4: add BROTLI_PARAM_LGWIN=24 to brotliCompress() in generate-bundles.ts.
Increases back-reference window from 4 MB (default 22 bits) to 16 MB
(RFC 7932 max, browser-decodable). Expected saving: ~5-8 MB across
large cache bundles (cache-misc, cache-wasmfs, cache-debug).

P5: sort tar entries by (extension, path) immediately before createTar().
Adjacent structurally-similar files (.a, .pyc, etc.) improve brotli
back-reference density. Expected saving: ~2-4 MB across the tarball.

Author: tolstenko

tools/emception/scripts/generate-bundles.ts

@@ -112,6 +112,10 @@ function brotliCompress(data: Buffer, outPath: string): Promise<Buffer> {
       {
         params: {
           [zlib.constants.BROTLI_PARAM_QUALITY]: 11,
+          // P4: 16 MB back-reference window (RFC 7932 max = 24 bits).
+          // Node.js default is 22 bits (4 MB).  Large cache bundles have
+          // pattern repetitions spanning >4 MB, so this saves ~5–8 MB.
+          [zlib.constants.BROTLI_PARAM_LGWIN]: 24,
         },
       },
       (err, result) => {
@@ -534,6 +538,16 @@ async function main() {
       continue;
     }
 
+    // P5: Sort by extension then path so structurally similar files (e.g. all
+    // .a, all .pyc) are adjacent.  Brotli can then reference earlier identical
+    // or near-identical blocks within its window, improving ratios across the
+    // whole bundle (~2–4 MB saving across the tarball).
+    entries.sort((a, b) => {
+      const extA = path.extname(a.path);
+      const extB = path.extname(b.path);
+      return extA !== extB ? extA.localeCompare(extB) : a.path.localeCompare(b.path);
+    });
+
     // Create tar
     const tar = createTar(entries);
     totalUncompressed += tar.length;

tools/emception/scripts/stage-core-cdn.mjs

@@ -35,42 +35,23 @@ async function exists(filePath) {
 }
 
 async function resolveStagingSource() {
-    const candidates = [
-        {
+    // Only build/cdn is a valid source.  public/cdn and packages/core/cdn may
+    // contain stale bundles from a previous build and must NEVER be used as a
+    // silent fallback — that was the root cause of the v3.5.0 regression where
+    // the published tarball was 164 MB instead of ~150 MB.
+    if (await exists(sourceBuildCdnDir) && await exists(sourceBuildManifestFile)) {
+        return {
             label: 'build/cdn',
             cdnDir: sourceBuildCdnDir,
             manifestFile: sourceBuildManifestFile,
-        },
-        {
-            label: 'public/cdn',
-            cdnDir: sourcePublicCdnDir,
-            manifestFile: sourcePublicManifestFile,
-        },
-        {
-            label: 'packages/core/cdn',
-            cdnDir: targetCdnDir,
-            manifestFile: targetManifestFile,
-        },
-    ];
-
-    for (const candidate of candidates) {
-        if (await exists(candidate.cdnDir) && await exists(candidate.manifestFile)) {
-            if (candidate.cdnDir !== sourceBuildCdnDir) {
-                console.log(
-                    `[stage-core-cdn] ${path.relative(emceptionRoot, sourceBuildCdnDir)} unavailable; reusing ${path.relative(emceptionRoot, candidate.cdnDir)}.`,
-                );
-            }
-            return candidate;
-        }
+        };
     }
 
     throw new Error(
         [
             'Unable to stage the emception core CDN.',
-            'Expected one of these artifact sets to exist:',
-            `- ${path.relative(emceptionRoot, sourceBuildCdnDir)} + ${path.relative(emceptionRoot, sourceBuildManifestFile)}`,
-            `- ${path.relative(emceptionRoot, sourcePublicCdnDir)} + ${path.relative(emceptionRoot, sourcePublicManifestFile)}`,
-            `- ${path.relative(emceptionRoot, targetCdnDir)} + ${path.relative(emceptionRoot, targetManifestFile)}`,
+            `build/cdn artifacts not found at: ${sourceBuildCdnDir}`,
+            'Run `npm run build:cdn:serial` (or `npm run build:all`) first.',
         ].join('\n'),
     );
 }