Resolve SSH config Include directives in host completion

[lucieleblanc]

Summary

The SSH host generator was hardcoded to cat ~/.ssh/config, which only reads the main config file. Users with configs split across included files via Include directives (e.g. Include conf.d/*) got no host suggestions for hosts defined in those files.

Fixes: APP-3506
See: #4072, #5900, #3708

Changes

Replaced the cat ~/.ssh/config command in both the hosts and addresses generators with a command that:

1. Uses awk to extract Include paths from ~/.ssh/config
2. Resolves ~ to $HOME
3. Treats relative paths as relative to ~/.ssh/ (per SSH spec)
4. Lets the shell expand glob patterns in Include paths
5. Reads all included files alongside the main config

The known_hosts generator is unchanged since ~/.ssh/known_hosts doesn't use Include directives.

Testing

• All 11 existing tests pass, including all_command_specs_have_no_newlines (TMUX safety) and all_referenced_generators_exist.
• Manually verified with mock SSH configs that both relative (conf.d/*) and absolute (/path/to/conf.d/*) Include paths resolve correctly.

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Conversation: https://staging.warp.dev/conversation/c78432f4-e7f9-4799-a3be-fc2b53cac149
Run: https://oz.staging.warp.dev/runs/019d473b-6e27-7de1-8c6c-90d7629402cd

This PR was generated with Oz.

[linear]

APP-3506 Resolve SSH config Include directives in host completion

Spec + generator exist, but the SSH host generator is hardcoded to cat ~/.ssh/config (confirmed in command-signatures/src/generators/ssh.rs). It does NOT resolve Include directives, so users with configs split across included files (e.g. Include conf.d/*) get no host suggestions.

Fix: Change generator to use ssh -G '' 2>/dev/null or manually parse Include directives.

See GitHub #4072, #5900, #3708

[lucieleblanc]

SSH Completions with Include Directive Resolution — Visual Verification

Test Setup

• ~/.ssh/config contains an Include config.d/* directive and 2 hosts (main-server, dev-box)
• ~/.ssh/config.d/work contains 2 hosts (work-vpn, staging-env)
• ~/.ssh/config.d/personal contains 2 hosts (home-nas, cloud-vm)

Result

Typing ssh and pressing Tab triggers the completions dropdown showing all 6 hosts from both the main config and included config files:

All hosts are correctly resolved:

1. cloud-vm — SSH Host (from included file config.d/personal)
2. dev-box — SSH Host (from main config)
3. home-nas — SSH Host (from included file config.d/personal)
4. main-server — SSH Host (from main config)
5. staging-env — SSH Host (from included file config.d/work)
6. work-vpn — SSH Host (from included file config.d/work)

✅ The hosts generator correctly resolves SSH Include directives and shows completions from all included config files.