A drop-in destination change no longer makes a landing verify every bundle

landing-preconditions verified EVERY bundle whenever vite.doxa-maps-build-config.json changed, but two
of its keys build nothing: dropin (where sync-dropin copies to) and the "//" comment keys. Changing
dropin.dest cost a full verification, about 10 minutes, for no possible staleness. The config now counts
as a build change only when another key differs. Checked on real history both ways: the dropin.dest fix
is not a build change; the posterSources flip is.

internal/landing-preconditions.mjs

@@ -117,7 +117,22 @@ if (process.env.DOXA_SKIP_FRESHNESS === '1') {
     const deps = (ref) => { try { const j = JSON.parse(run('git', ['show', `${ref}:package.json`]).stdout); return JSON.stringify([j.dependencies, j.devDependencies]) } catch { return '' } }
     return deps(base) !== deps('HEAD')
   }
-  const everything = !base || pkgDepsChanged() || changed.some((f) => /^(vite\.config\.js$|bun\.lockb?$|vite\.doxa-maps-build-config\.json$)/.test(f))
+  // The build config reaches every bundle only through a key the BUILD reads. dropin (where sync-dropin copies
+  // to) and the "//" comment keys build nothing: a dropin.dest fix verified every bundle, ~10 min, for nothing.
+  const buildCfgChanged = () => {
+    const CFG = 'vite.doxa-maps-build-config.json'
+    if (!changed.includes(CFG) || !base) return false
+    const keys = (ref) => {
+      try {
+        const j = JSON.parse(run('git', ['show', `${ref}:${CFG}`]).stdout)
+        for (const k of Object.keys(j)) if (k === 'dropin' || k.startsWith('//')) delete j[k]
+        return JSON.stringify(j)
+      } catch { return null }
+    }
+    const a = keys(base), b = keys('HEAD')
+    return a === null || b === null || a !== b
+  }
+  const everything = !base || pkgDepsChanged() || buildCfgChanged() || changed.some((f) => /^(vite\.config\.js$|bun\.lockb?$)/.test(f))
   const libChanged = changed.filter((f) => f.startsWith('library/'))
   const shared = everything || libChanged.length > 0
   const own = new Set(changed.map((f) => (f.match(/^plugin-designs\/([^/]+)\//) || [])[1]).filter(Boolean))