ui/phase-22: skip the no-op stance click in the races table

Clicking the already-active WAR/PEACE button still appended a
\`setDiplomaticStance\` whose \`relation\` matched the row's current
value. The engine would accept the duplicate harmlessly, but the
order tab inflates with rows that say nothing and every auto-sync
re-ships the redundant payload. Compare against the overlayed
stance (so a queued-but-not-applied change suppresses a re-click
that matches the *intended* state, not just the server snapshot)
and short-circuit when they agree. Mirrors the vote picker, which
already had the same guard.

vitest.config.ts: \`mergeConfig\` refuses callback-form base
configs, so resolve \`vite.config.ts\`'s callback with the test
context first and merge the plain object. Surfaced after the
\`loadEnv\` migration switched the root config to the callback
form.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

ui/frontend/src/lib/active-view/table-races.svelte

@@ -148,6 +148,15 @@ data fetching is performed here — the layout is responsible.
 
 	async function setStance(acceptor: string, relation: Relation): Promise<void> {
 		if (draft === undefined) return;
+		// No-op when the row already reflects the requested stance — the
+		// engine would accept the duplicate, but queueing a wire entry
+		// that re-states the current state inflates the order tab and
+		// the auto-sync envelope for nothing. The current stance reads
+		// off the overlay (`races[i].relation`), so a queued-but-not-
+		// applied stance change correctly suppresses a duplicate click
+		// that matches the *queued* intent, not just the server snapshot.
+		const current = races.find((r) => r.name === acceptor)?.relation;
+		if (current === relation) return;
 		await draft.add({
 			kind: "setDiplomaticStance",
 			id: crypto.randomUUID(),