fix(css): give the unminified-CSS warning a remedy that works

src/html/styles-builder/css-provider-session.test.ts

@@ -208,12 +208,15 @@ describe("styles-builder CSS provider sessions", () => {
     assertEquals(generated.css, "missing-optimizer|sheet|alpha");
   });
 
-  it("reports a missing optimizer once, with the package that provides one", () => {
+  it("reports a missing optimizer once, with the steps that actually enable one", () => {
     // `regenerateCSSByHash` acquires a session per request, so warning on every
     // acquisition made this line the most frequent entry in a hosted project's
-    // logs -- once per render, at warn level, naming a registration hook with no
-    // documented way to act on it. State the package that registers an engine,
-    // and say it once while the engine stays absent.
+    // logs -- once per render, at warn level. Say it once while the engine stays
+    // absent, and give the whole recipe: `@veryfront/ext-css-lightning` declares
+    // `activation: "explicit"`, so installing the package registers nothing on
+    // its own. Only a `veryfront.config.ts` `extensions` entry activates it, and
+    // advice that stops at the install leaves the developer with unminified CSS
+    // and no next step.
     installProcessor(createProcessor("warn-rearm"));
     register(CSSOptimizationEngineName, createOptimizer("warn-rearm"));
     // Observing an engine re-arms the warning, so this test does not depend on
@@ -236,10 +239,19 @@ describe("styles-builder CSS provider sessions", () => {
       __resetLogRecordEmitterForTests();
     }
 
-    const reports = records.filter((entry) => entry.message.includes("CSSOptimizationEngine"));
+    const reports = records.filter((entry) => entry.message.includes("unminified CSS"));
     assertEquals(reports.length, 1);
+    const report = reports[0]?.message ?? "";
     assertEquals(reports[0]?.level, "warn");
-    assertEquals(reports[0]?.message.includes("@veryfront/ext-css-lightning"), true);
+    assertEquals(report.includes("@veryfront/ext-css-lightning"), true);
+    assertEquals(report.includes("veryfront.config.ts"), true);
+    assertEquals(report.includes("extensions"), true);
+    // `deno add` is wrong twice over: scaffolded projects are npm projects, and
+    // no package manager can activate an explicit-activation extension.
+    assertEquals(report.includes("deno add"), false);
+    // The contract name is an internal registration hook the guides never
+    // mention, so it cannot appear as the developer-facing instruction.
+    assertEquals(report.includes("CSSOptimizationEngine"), false);
   });
 
   it("keeps minified and unminified output in separate cache identities", async () => {

src/html/styles-builder/tailwind-compiler.ts

@@ -149,14 +149,24 @@ export function acquireCSSGenerationSession(minify: boolean): CSSGenerationSessi
     //
     // Once per process, not once per acquisition: regenerateCSSByHash acquires
     // a session on every cold-cache request, which made this the single most
-    // frequent line in a hosted project's logs. Name the package that registers
-    // an engine, or the message asks for a hook with no way to reach it.
+    // frequent line in a hosted project's logs.
+    //
+    // State the effect and the whole remedy. An earlier revision borrowed
+    // `resolve()`'s "install it with: deno add <package>" hint, which is only
+    // true for an auto-activating extension: `@veryfront/ext-css-lightning`
+    // declares `activation: "explicit"`, so installing it registers nothing
+    // until a `veryfront.config.ts` `extensions` entry activates it, and
+    // scaffolded projects are npm projects where `deno add` is the wrong
+    // command besides. Advice that stops at the install reads as actionable and
+    // leaves the CSS exactly as unminified as before. The contract name stays
+    // out of the instruction: it is an internal registration hook the guides
+    // never mention, and `component=css-compiler` already identifies the source.
     reportedMissingOptimizationEngine = true;
     const recommendation = getRecommendation(CSSOptimizationEngineName);
     logger.warn(
       recommendation === undefined
-        ? "No CSSOptimizationEngine registered; emitting unminified CSS"
-        : `No CSSOptimizationEngine registered; emitting unminified CSS. Install one with: deno add ${recommendation}`,
+        ? "Veryfront emits unminified CSS because no CSS optimizer is active"
+        : `Veryfront emits unminified CSS because no CSS optimizer is active. Install ${recommendation}, then add it to "extensions" in veryfront.config.ts`,
     );
   }
   const optimizationEngine = optimizationProvider === undefined