Add speech voice clone and design commands

[octo-patch]

Reason: Add voice cloning and voice design support to the speech CLI and SDK.

Changes:

• Add voice clone and voice design endpoint helpers and response/request types.
• Add mmx speech clone and mmx speech design commands.
• Add speech SDK helpers for clone/design and clone/prompt audio upload purposes.
• Cover the new command registry entries, dry-run payloads, and SDK request parsing with tests.

Checks:

• bun test test/commands/speech/clone.test.ts test/commands/speech/design.test.ts test/sdk/speech.test.ts test/commands/aliases.test.ts
• bun run typecheck
• bun run lint
• bun test

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