fix(cli): escape claude args and stop aborting on exit in omniroute launch

[sumanxg]

Summary

Two Windows bugs in omniroute launch, both in bin/cli/commands/launch.mjs. Found while launching Claude Code through a local OmniRoute on Windows 11 / Node 24.18.0.

1. Pass-through arguments are truncated at the first space

spawn(..., { shell: true }) (added in #8283 to resolve the claude.cmd shim) joins argv with plain spaces and no escaping — this is exactly what Node's DEP0190 warning printed on every launch is about. Any argument containing a space is split by cmd.exe.

$ omniroute launch --profile auto-best-coding -p "In one short line: say BANANA"
# claude receives: -p In        (plus "one", "short", ... as stray positionals)
# model replies: "It looks like your message got cut off — you typed 'In'..."

Fixed by escaping each argument for cmd.exe: CRT argv rules first (double the backslashes preceding a quote, escape embedded quotes, wrap in quotes), then cmd metacharacters caret-escaped twice. The second pass is required because claude.cmd is an npm shim that re-parses %* on the way to node — with a single pass, arguments still truncate at the first & or |. (Same rule as cross-spawn's doubleEscapeMetaChars.)

After:

$ omniroute launch --profile auto-best-coding -p "In one short line: say BANANA & MANGO"
BANANA & MANGO

2. Any non-zero exit aborts the process with a libuv assertion

The command action called process.exit(exitCode), tearing the loop down while the exited child's inherited stdio handles were still closing:

$ omniroute launch --profile auto-best-coding     # with claude not on PATH
The 'claude' CLI was not found in PATH.
Assertion failed: !(handle->flags & UV_HANDLE_CLOSING), file src\win\async.c, line 94
# exit code 0xC0000409 instead of claude's exit code

Fixed by setting process.exitCode and letting the loop drain. Verified a child exiting 3 now propagates as 3, and the process still terminates promptly (~1.9s, no hang).

This one is not limited to the ENOENT path — it fired on any non-zero exit from claude.

Changes

• bin/cli/commands/launch.mjs — adds exported resolveClaudeSpawn() (extracts the existing inline platform choice, mirroring the resolveCodexSpawn() precedent) and quoteClaudeArgs(); process.exit() → process.exitCode.
• tests/unit/cli/launch-windows-spawn-args.test.ts — new, 7 tests.

No new dependencies; the escaping is a few lines rather than pulling in cross-spawn.

Tests

Test files added/changed: tests/unit/cli/launch-windows-spawn-args.test.ts

$ node --import tsx/esm --test tests/unit/cli/launch-windows-spawn-args.test.ts
# tests 7 / pass 7 / fail 0

# no regressions in the neighbouring CLI suites
$ node --import tsx/esm --test tests/unit/cli/launch-command.test.ts \
    tests/unit/cli/launch-codex.test.ts \
    tests/unit/launch-codex-windows-spawn-6312.test.ts
# tests 11 / pass 11 / fail 0

$ npm run lint
# 1 problem (1 error, 0 warnings) — pre-existing, unrelated to this PR:
#   src/app/(dashboard)/dashboard/settings/components/ProviderAccountRoutingCard.tsx
#   87:5 react-hooks/exhaustive-deps — useCallback missing dependency 'load'
# That file is byte-identical to release/v3.8.49 on this branch
# (`git diff origin/release/v3.8.49 --name-only` lists only the two files above).
# Left untouched so this PR stays scoped — flagging it in case it is news.

The test written red-first against both bugs, then green after the fix. Coverage of the encoding is split deliberately so CI still guards it:

• Golden-string assertions pin the exact escaped output for 8 inputs (flags, spaces, &, embedded quote, trailing backslash, %PATH%, empty string). Pure function, so these run on Linux CI.
• A Windows-only round-trip test spawns a real npm-style .cmd shim (@echo off + node "%~dp0argv.mjs" %*) through the same shell: true path and asserts argv arrives byte-identical. Skips off-Windows with a stated reason.

I verified the golden assertions actually bite: reducing the double caret-escape back to a single pass turns them red, which is the case Linux CI would otherwise miss entirely.

Notes for reviewers

• bin/cli/commands/launch-codex.mjs carries the identical defect — same shell: true concatenation, same process.exit(). It is currently masked because its generated -c args contain no spaces, but any user pass-through arg with a space breaks the same way. Left unchanged here to keep this PR scoped; happy to port both fixes in a follow-up if you'd like them together.
• The double caret-escape is correct only while the Windows target is a .cmd shim. resolveClaudeSpawn() guarantees that today, but the two are coupled by convention rather than structure — worth a comment or an assertion if the spawn target ever becomes configurable.
• DEP0190 still prints on every Windows launch. It is now inaccurate (the args are escaped), but silencing it means restructuring the spawn, so I left it alone.