chore(format): run prettier over src/ and scripts/

Formatting was configured but never enforced: `bun run format:check`
reported 199 unformatted files and ran in no workflow and in no git hook,
so .prettierrc (printWidth 100, trailing commas) described an intention
rather than the tree.

This is the one-time sweep that makes the check gateable. Whitespace and
token-reflow only -- no behavioural change: `bun run check` reports 0
errors and all 1053 frontend tests pass before and after.

Kept out of every other commit on purpose. A 199-file diff mixed with
real changes is unreviewable, and the next commit turns format:check
into a hard CI gate so this cannot silently accumulate again.

scripts/extract-traces.test.ts

@@ -140,9 +140,10 @@ describe("findDanglingIds", () => {
   });
 
   it("deduplicates and sorts, so one typo is reported once", () => {
-    expect(
-      findDanglingIds(["DR-189", "DR-189", "UR-999", "DR-189"], defined)
-    ).toEqual(["DR-189", "UR-999"]);
+    expect(findDanglingIds(["DR-189", "DR-189", "UR-999", "DR-189"], defined)).toEqual([
+      "DR-189",
+      "UR-999",
+    ]);
   });
 
   it("ignores IDs whose prefix is not a known trace type", () => {
@@ -158,7 +159,7 @@ describe("coverage threshold", () => {
     // passes, which is how the 50%-while-actually-86% slack went unnoticed.
     const workflow = fs.readFileSync(
       path.resolve(HERE, "../.gitea/workflows/traceability-check.yml"),
-      "utf-8"
+      "utf-8",
     );
     const match = workflow.match(/^\s*MIN_THRESHOLD=(\d+)\s*$/m);
     expect(match).not.toBeNull();
@@ -307,9 +308,7 @@ describe("generated matrix file links", () => {
 
   it("keeps the #Lnn line anchor on the href", () => {
     const link = formatMatrixFileLink("scripts/extract-traces.ts", 427);
-    expect(link).toBe(
-      "[`scripts/extract-traces.ts`](../scripts/extract-traces.ts#L427)"
-    );
+    expect(link).toBe("[`scripts/extract-traces.ts`](../scripts/extract-traces.ts#L427)");
   });
 
   it("does not produce a bare repo-root href, which resolves to docs/<path>", () => {
@@ -334,10 +333,7 @@ describe("live requirements.md", () => {
     // row. Worse, the pins never guarded the actual defect — a stale denominator
     // is caught by the sum-consistency check below, and the >100% ratio it
     // produced is covered directly by the computeCoverage tests, on fixtures.
-    const md = fs.readFileSync(
-      path.resolve(HERE, "../docs/requirements.md"),
-      "utf-8"
-    );
+    const md = fs.readFileSync(path.resolve(HERE, "../docs/requirements.md"), "utf-8");
     const defined = countDefinedRequirements(md);
 
     // The parser found real rows of every type: a section silently failing to