fix(ui): quote YAML scalars containing embedded newlines (#7820)

yamlScalar decided a value needs quoting from value.trim() !== value plus
a special-character regex. trim() only strips edge whitespace, and the
regex omitted line breaks, so a value with an embedded newline and no other
flagged character (e.g. "claude 3.7\nignore_findings true") was emitted as
a raw multi-line scalar -- a stray top-level line that breaks the generated
.loopover.yml, violating the file's "a partial form never produces invalid
output" invariant. Same incomplete-guard bug class as the csv-export fix.

Add \n and \r to the needsQuote regex so any line-break-containing value
goes through the existing JSON.stringify quoting path. Adds embedded-newline
and carriage-return regression cases to config-generator-yaml.test.ts.

Closes #7786

Co-authored-by: jaytbarimbao-collab <300663773+jaytbarimbao-collab@users.noreply.github.com>

Author: jaytbarimbao-collab

apps/loopover-ui/src/lib/config-generator-yaml.test.ts

@@ -76,4 +76,24 @@ describe("formStateToYaml", () => {
       [HEADER, "gate:", "  aiReview:", `    model: ${JSON.stringify(" claude ")}`].join("\n"),
     );
   });
+
+  // Regression (#7786): an embedded newline is not caught by trim() (which only strips edges) and is
+  // none of the flagged special chars, so the old guard emitted it as a raw multi-line scalar that
+  // broke the generated .loopover.yml with a stray top-level line.
+  it("quotes a model value containing an embedded newline", () => {
+    const model = "claude 3.7\nignore_findings true";
+    const output = formStateToYaml({ gate: { aiReview: { model } } });
+    expect(output).toBe(
+      [HEADER, "gate:", "  aiReview:", `    model: ${JSON.stringify(model)}`].join("\n"),
+    );
+    // The serialized value must stay on a single line -- no stray line beyond the 4 expected ones.
+    expect(output.split("\n")).toHaveLength(4);
+  });
+
+  it("quotes a model value containing a carriage return", () => {
+    const model = "claude\r3.7";
+    expect(formStateToYaml({ gate: { aiReview: { model } } })).toBe(
+      [HEADER, "gate:", "  aiReview:", `    model: ${JSON.stringify(model)}`].join("\n"),
+    );
+  });
 });

apps/loopover-ui/src/lib/config-generator-yaml.ts

@@ -25,10 +25,13 @@ export type GeneratorFormState = {
 const YAML_HEADER = "# .loopover.yml — generated by the config generator";
 
 /** Plain-scalar YAML value needs quoting when it would otherwise be ambiguous (a YAML special
- *  character, leading/trailing whitespace, or the empty string). Model names are free text, so this
- *  is a real correctness need, not defensive-for-its-own-sake. */
+ *  character, an embedded line break, leading/trailing whitespace, or the empty string). Model names
+ *  are free text, so this is a real correctness need, not defensive-for-its-own-sake. `value.trim()`
+ *  only catches whitespace at the edges, so an embedded `\n`/`\r` must be flagged explicitly (#7786)
+ *  or `formStateToYaml` would emit it as a raw, file-breaking multi-line scalar. */
 function yamlScalar(value: string): string {
-  const needsQuote = value === "" || value.trim() !== value || /[:#[\]{}&*!|>'"%@`,]/.test(value);
+  const needsQuote =
+    value === "" || value.trim() !== value || /[\n\r:#[\]{}&*!|>'"%@`,]/.test(value);
   return needsQuote ? JSON.stringify(value) : value;
 }