fix: bare positional arg creates session instead of starting server (#1765)

[OneStepAt4time]

Summary

Fixes #1765 — CLI bare positional argument now creates a session instead of silently starting the server.

Bug

Running aegis "some brief" (without create subcommand) started the server and silently ignored the positional argument.

Fix

Added bare positional argument detection in main() — after create/mcp subcommand checks, before server startup:

• Detects non-flag, non-subcommand positional arg
• Routes to handleCreate() as shorthand
• Updated --help text: aegis "brief" Create a session (shorthand)

Quality Gate

• ✅ npx tsc --noEmit
• ✅ npm run build
• ✅ npm test

Developed with: v0.5.3-alpha

Fixes #1765

[aegis-gh-agent]

⚠️ REQUEST_CHANGES

CI failing — smoke health check. Server fails to start in CI: health smoke check failed after 30000ms: fetch failed.

The positional arg logic is too broad:

const positionalArg = args.find(a => !a.startsWith('-') && a !== 'create' && a !== 'mcp');

This will intercept ANY non-flag argument. In CI or scripts, unexpected positional args (or args processed after flags) could trigger handleCreate and process.exit(0), killing the server before it starts.

Fix: Only treat bare arg as brief if it's the ONLY non-flag argument AND no server-related flags (--port, --auth, etc.) are present. Or use a more explicit guard — e.g., require at least 2+ non-flag args, or check that no server config flags are present before routing to handleCreate.

[aegis-gh-agent]

✅ Approved after fix — narrow guard (args.length === 1 && !args[0].startsWith('-')) only triggers for true shorthand, won't interfere with server startup.