fix(observability-map): print the unknown-suppression warning once

The CLI sent the warning to stderr for the whole-report path and renderTerminal
embedded the same lines in the stdout report body, so a plain run showed every
warning twice. Stderr now carries it only when stdout is JSON a caller parses,
which is the reason that loop existed. The terminal report keeps it in the
body, so redirecting stdout to a file loses nothing.

The single-route path is unchanged: its terminal output never carried the
warning, so it never duplicated.

Author: 1stvamp

internal-packages/observability-map/src/cli.test.ts

@@ -155,14 +155,29 @@ describe("map", () => {
   });
 });
 
-// B6. Stdout can be JSON a caller parses, so the warning goes to stderr in every mode, and the
-// terminal report carries it too (see report.test.ts).
+// B6. Stdout can be JSON a caller parses, so the warning goes to stderr whenever stdout is JSON.
+// The terminal report carries it in its body instead (`src/report/terminal.test.ts`), and printing
+// it on both streams meant a plain run showed every warning twice.
 describe("warning about a suppression that names no check", () => {
-  it("names the file and the bad id on stderr for the whole report", () => {
+  it("names the file and the bad id in the whole report", () => {
     const r = run("--no-write");
     expect(r.code).toBe(0);
+    expect(r.out).toContain("api.v1.typo.ts");
+    expect(r.out).toContain("eror-classification");
+  });
+
+  it("prints the warning once for a terminal run of the whole report", () => {
+    const r = run("--no-write");
+    const lines = `${r.out}${r.err}`.split("\n").filter((l) => l.startsWith("UNKNOWN SUPPRESSION"));
+    expect(lines).toHaveLength(1);
+  });
+
+  it("names the file and the bad id on stderr when the whole report is json", () => {
+    const r = run("--no-write", "--json");
+    expect(r.code).toBe(0);
     expect(r.err).toContain("api.v1.typo.ts");
     expect(r.err).toContain("eror-classification");
+    expect(r.out).not.toContain("UNKNOWN SUPPRESSION");
   });
 
   it("warns for a single route without putting the warning in the json", () => {

internal-packages/observability-map/src/cli.ts

@@ -130,7 +130,10 @@ export function main(argv: string[], io: Io = processIo): number {
   }
 
   const report = buildReport(entryPoints, parseFailures);
-  for (const line of unknownSuppressionLines(report)) io.err(`${line}\n`);
+  // JSON only. `renderTerminal` puts these lines in the report body, so warning here as well
+  // printed each one twice in a terminal run. Stderr is what the JSON path has instead, since a
+  // warning on stdout would be inside the document a caller parses.
+  if (asJson) for (const line of unknownSuppressionLines(report)) io.err(`${line}\n`);
   io.out(asJson ? renderJson(report) : renderTerminal(report));
   io.out("\n");
   if (!noWrite) {