feat(config): add profile list/rename/delete and clearer arg errors

[n8agrin]

Closes #45.

Background

The issue reported omni config use Playground Org-scoped failing with a cryptic accepts 1 arg(s), received 2. The root cause is plain shell tokenization — the name has a space and needs quoting (omni config use "Playground Org-scoped" works fine). But the CLI made the situation worse in two ways:

1. The error was opaque — it didn't hint that quoting was the fix.
2. There was no in-CLI way to manage profiles, so the reporter had to sudo-edit the JSON to rename/delete a badly-named profile.

The issue offered two directions: forbid spaces on save, or allow them and make them usable. This PR takes the "allow them" path — spaced/parenthesized names work fine when quoted, and the config format is shared with the TS CLI, so refusing to create names the TS CLI allows would be inconsistent. Instead it fixes the ergonomics around such names and adds the lifecycle CRUD the issue also asked for.

Changes

• omni config list — lists profiles, marking the default with * (plus auth method + endpoint).
• omni config rename <old> <new> — the recovery path for a badly-named profile, no JSON editing required. Refuses to overwrite an existing profile and moves defaultProfile along if it pointed at the old name.
• omni config delete <name> — interactive [y/N] confirmation by default (--yes/-y to skip). Clears defaultProfile when it referenced the deleted profile.
• Clearer multi-word arg errors — use/login/logout/delete share a profileNameArgs validator. When the shell passes more than one token (the exact Config profile lifecycle management #45 case), the error names the likely-intended profile already quoted:

  got 2 arguments — a profile name is a single value; if it contains spaces,
  quote it: omni config use "Playground Org-scoped"
  

• "not found" errors list available profiles quoted, so spaced names are visually distinct.

No validation is added on save — spaced/special names are allowed; quoting at the shell is the user's responsibility.

Why not forbid spaces?

An earlier revision of this PR did exactly that (strict [A-Za-z0-9_.-] allowlist). Dropped because: quoting args is standard shell behavior, the allowlist forbade reasonable display names (My Org (prod), client: acme), it was a mild behavior change for anyone scripting config init --name, and it diverged from the TS CLI which shares the on-disk format. The CRUD + better errors solve the reported pain without the policy.

Notes for reviewers

• Rebased onto main on top of feat: add flags to omni config init for non-interactive setup #63 (non-interactive config init flags). Net diff touches only cmd/omni/config_commands*.go — internal/config is unchanged from main.
• config use remains single-name; the two-positional config rename is unambiguous, so a spaced target name there works without quoting gymnastics.

Test plan

• go test ./... green
• omni config use Foo Bar (unquoted) → quoting hint naming "Foo Bar"
• omni config use "Playground Org-scoped" → switches profiles
• omni config init --name "My Org (prod)" … → allowed
• omni config list marks the default
• omni config rename prod "Production (US)" → renames, updates default
• omni config delete name prompts; --yes skips

🤖 Generated with Claude Code

[dspangen]

lgtm