Fix nuke preview showing teammate SAMs as threats (#4342)

## Problem

In the nuke trajectory preview, the SAM-intercept **"X"** marker was
drawn over **teammates'** SAMs — implying their SAM would shoot down
your missile. It shouldn't: like allies, a teammate's SAM never engages
your nuke. The bug only affected teammates; allies already worked.

## Cause

The preview built its threat set from `myPlayer.allies()` only — formal
alliances — and never considered teammates. That diverged from the sim
([`SAMLauncherExecution.ts`](src/core/execution/SAMLauncherExecution.ts#L118-L134)),
which skips any nuke whose owner it's `isFriendly()` with (**same team
OR allied**).

## Fix

`samThreatensNukePreview` now takes a teammate set and excludes
teammates **unconditionally**.

The subtlety: allies keep the existing *betrayal* exception — a strike
close enough to break the alliance makes that ally's SAM engage at
launch (`listNukeBreakAlliance`, the same function the sim uses).
Teammates get **no** such exception, because a strike can break an
alliance but never a team relationship. So even a player who is both a
teammate *and* a betrayed ally is correctly left off the threat set.

## Notes

- The sim has an "aftergame fun" exception where teammate SAMs *do*
target teammate nukes once there's a winner. The preview only appears
while aiming a buildable mid-game (no winner yet), so that case doesn't
apply here.

## Tests

Updated `samThreatensNukePreview` unit tests for the new signature and
added coverage for: teammate excluded, and teammate stays excluded even
when listed as betrayed. All 11 tests pass.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

tests/client/controllers/BuildPreviewController.test.ts

@@ -35,21 +35,40 @@ describe("BuildPreviewController ghost preservation (locked nuke / Enter confirm
 });
 
 describe("samThreatensNukePreview (nuke trajectory threat set, #4226)", () => {
+  const teammates = new Set([7, 8]);
   const allies = new Set([2, 3]);
 
-  test("non-allied SAM threatens the trajectory", () => {
-    expect(samThreatensNukePreview(5, allies, new Set())).toBe(true);
+  test("non-friendly SAM threatens the trajectory", () => {
+    expect(samThreatensNukePreview(5, teammates, allies, new Set())).toBe(true);
   });
 
   test("allied SAM does not threaten when the strike breaks no alliance", () => {
-    expect(samThreatensNukePreview(2, allies, new Set())).toBe(false);
+    expect(samThreatensNukePreview(2, teammates, allies, new Set())).toBe(
+      false,
+    );
   });
 
   test("would-be-betrayed ally's SAM threatens (alliance breaks at launch)", () => {
-    expect(samThreatensNukePreview(2, allies, new Set([2]))).toBe(true);
+    expect(samThreatensNukePreview(2, teammates, allies, new Set([2]))).toBe(
+      true,
+    );
   });
 
   test("other allies' SAMs still excluded when a different ally is betrayed", () => {
-    expect(samThreatensNukePreview(3, allies, new Set([2]))).toBe(false);
+    expect(samThreatensNukePreview(3, teammates, allies, new Set([2]))).toBe(
+      false,
+    );
+  });
+
+  test("teammate SAM does not threaten the trajectory", () => {
+    expect(samThreatensNukePreview(7, teammates, new Set(), new Set())).toBe(
+      false,
+    );
+  });
+
+  test("teammate SAM stays excluded even if listed as betrayed (a strike never breaks a team)", () => {
+    expect(
+      samThreatensNukePreview(7, teammates, new Set([7]), new Set([7])),
+    ).toBe(false);
   });
 });