docs: revise presentation slides after epic completion

[joshrotenberg]

The presentation slides (docs/docs/presentation/index.md and docs/docs/presentation/slides.html) use outdated CLI syntax throughout:

• Old flags: --cloud-api-key, --cloud-secret-key, --enterprise-url, --enterprise-user, --enterprise-password
• Old commands: profile set-default
• Old TOML fields: cloud_api_key

Rather than patching these incrementally, do a full revision once the current epics are complete. The slides can be tightened up to reflect the final state of the CLI including:

• Current flag names (--api-key, --api-secret, --url, --username, --password)
• Per-type defaults (profile default-cloud, profile default-enterprise, profile default-database)
• profile init wizard
• Profile tags
• profile current for shell integration
• Platform inference (prefix-optional commands)
• profile validate --connect
• Database profiles

Blocked until current epics wrap up.