fix(build): the fused output's .exe follows the TARGET, not the host

`clode build`'s default output name keyed its .exe suffix off process.platform
(the build host), which got cross-builds exactly backwards: `--target windows-x64`
from a POSIX host produced a `quaude` with no .exe (unrunnable on Windows until
renamed), and a POSIX `--target` built FROM Windows produced a spurious `.exe`.

Extract the naming into a pure, exported defaultBuildOut({target, self,
hostPlatform}): a windows-* target is .exe regardless of host, a non-windows
target never is, and with no --target it follows the host (native builds
unchanged). Explicit --out is still respected verbatim. Unit-tested across the
cross-build matrix (windows-from-POSIX, POSIX-from-Windows, native, --self).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_0147MaTTj7XYS2PTUmJn3zUy

Author: schmonz

libexec/clode-fuse.cjs

@@ -709,6 +709,17 @@ function parseBuildArgs(args) {
   return { naude, self, out, target, listTargets };
 }
 
+// Default output basename for a quaude/--self build (the naude branch names its
+// own). The `.exe` suffix follows the TARGET platform, not the host: a
+// `--target windows-*` cross-built from POSIX must still be a .exe, and a POSIX
+// `--target` built FROM Windows must NOT be. With no --target (a native build)
+// it follows the host. An explicit --out is respected verbatim by the caller.
+function defaultBuildOut({ target, self, hostPlatform }) {
+  const name = self ? 'clode-native' : 'quaude';
+  const isWin = target ? /^windows-/.test(target) : hostPlatform === 'win32';
+  return name + (isWin ? '.exe' : '');
+}
+
 // The default GitHub release download root. Overridable via CLODE_RELEASE_BASE
 // (forks / mirrors). No trailing slash.
 const CLODE_RELEASE_BASE_DEFAULT = 'https://github.com/schmonz/clode/releases/download';
@@ -1001,11 +1012,10 @@ async function clodeBuild(args, opts) {
   }
 
   // naude/self/out were already parsed + validated above (shared with the
-  // --naude branch, which returned before reaching here). On Windows a bare
-  // `clode build` should yield a runnable .exe. An explicit
-  // --out is respected verbatim (the user owns that name); only the DEFAULT
-  // gains .exe. win32-guarded → POSIX default (quaude / clode-native) unchanged.
-  out = path.resolve(out || (self ? 'clode-native' : 'quaude') + (process.platform === 'win32' ? '.exe' : ''));
+  // --naude branch, which returned before reaching here). The default name's
+  // .exe follows the TARGET, not the host (see defaultBuildOut); an explicit
+  // --out is respected verbatim (the user owns that name).
+  out = path.resolve(out || defaultBuildOut({ target: parsed.target, self, hostPlatform: process.platform }));
 
   const ROOT = path.resolve(opts.libexec, '..');
   const work = fs.mkdtempSync(path.join(os.tmpdir(), 'clode-build-'));
@@ -1393,7 +1403,7 @@ async function clodeBuild(args, opts) {
 }
 
 module.exports = {
-  clodeBuild, parseBuildArgs, makePhaseSpinner, startPongMock, cannedSSE, smokeTarget, timeoutScale, codesignAdHoc, thinToHostSlice, describeExit,
+  clodeBuild, parseBuildArgs, defaultBuildOut, makePhaseSpinner, startPongMock, cannedSSE, smokeTarget, timeoutScale, codesignAdHoc, thinToHostSlice, describeExit,
   readDirectDeps, computeDepClosure, assertClosureMatchesLockfile,
   scanBareSpecifiers, specifierPackageName, isBuiltinSpecifier, shimProvidedModules,
   assertNoUnknownBareSpecifiers, KNOWN_UNREACHABLE, resolveClaudeNmDir,

test/clode-fuse-args.test.cjs

@@ -1,7 +1,7 @@
 'use strict';
 const { test } = require('node:test');
 const assert = require('node:assert');
-const { parseBuildArgs } = require('../libexec/clode-fuse.cjs');
+const { parseBuildArgs, defaultBuildOut } = require('../libexec/clode-fuse.cjs');
 
 test('parseBuildArgs: --list-targets', () => {
   assert.deepStrictEqual(parseBuildArgs(['--list-targets']),
@@ -26,3 +26,22 @@ test('parseBuildArgs: plain build unchanged', () => {
   assert.deepStrictEqual(parseBuildArgs([]),
     { naude: false, self: false, out: null, target: null, listTargets: false });
 });
+
+// defaultBuildOut: the .exe suffix follows the TARGET platform, not the host —
+// the cross-build naming bug (keying off process.platform got both backwards).
+test('defaultBuildOut: .exe follows the target, not the host', () => {
+  // windows target from a POSIX host -> still .exe
+  assert.strictEqual(defaultBuildOut({ target: 'windows-x64', self: false, hostPlatform: 'linux' }), 'quaude.exe');
+  assert.strictEqual(defaultBuildOut({ target: 'windows-arm64', self: false, hostPlatform: 'darwin' }), 'quaude.exe');
+  // POSIX target from a Windows host -> NO .exe
+  assert.strictEqual(defaultBuildOut({ target: 'netbsd-sparc', self: false, hostPlatform: 'win32' }), 'quaude');
+  assert.strictEqual(defaultBuildOut({ target: 'linux-x64', self: false, hostPlatform: 'win32' }), 'quaude');
+});
+
+test('defaultBuildOut: no --target follows the host; --self names clode-native', () => {
+  assert.strictEqual(defaultBuildOut({ target: null, self: false, hostPlatform: 'win32' }), 'quaude.exe');
+  assert.strictEqual(defaultBuildOut({ target: null, self: false, hostPlatform: 'linux' }), 'quaude');
+  assert.strictEqual(defaultBuildOut({ target: null, self: true, hostPlatform: 'win32' }), 'clode-native.exe');
+  assert.strictEqual(defaultBuildOut({ target: 'windows-x64', self: true, hostPlatform: 'linux' }), 'clode-native.exe');
+  assert.strictEqual(defaultBuildOut({ target: null, self: true, hostPlatform: 'linux' }), 'clode-native');
+});