fix(cli): allow parent options after subcommand arguments

[cevr]

Summary

Follow-up to #5983. Extends parent option parsing to work across subcommand boundaries.

Enables parent/global options to appear anywhere in the command line, including after subcommand names and their arguments. This follows the common CLI pattern used by git, npm, docker, and most modern CLI tools.

Before

cli --global-opt subcommand arg     # works
cli subcommand arg --global-opt     # fails: "unknown option"

After

cli --global-opt subcommand arg     # works  
cli subcommand arg --global-opt     # works ✓

Motivation: The Centralized Flags Pattern

Many CLI applications define global options on the parent command that affect all subcommands:

const app = Command.make("app", {
  verbose: Options.boolean("verbose").pipe(Options.withAlias("v")),
  model: Options.text("model").pipe(Options.withAlias("m")),
}).pipe(
  Command.withSubcommands([process, export, list])
)

Users naturally expect to place these global options at the end of their command:

# Natural user expectation
app process input.txt -m gpt4 --verbose

# What was previously required  
app -m gpt4 --verbose process input.txt

This change removes that friction by extracting known parent options from anywhere in the args.

Implementation

1. getParentOptionNames() - Collects all option names (including aliases) from a parent command
2. extractParentOptionsFromArgs() - Scans args after the subcommand for known parent options and extracts them
3. Modified Subcommands case in parseInternal to use these helpers before splitting args

Uses Set for O(1) lookups on both subcommand names and parent option names.

Test Plan

• Added tests for parent options after subcommand args
• Added tests for parent option aliases after subcommand args
• Verified existing tests still pass (162 tests)
• Tested with --option=value format
• Tested mixed positioning (some before, some after subcommand)

🤖 Generated with Claude Code

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