fix: Revive Posthog's write only key

[jpmcb]

Description

This PR does the following:

• Exhumes the posthog reporting including the buildtime variable. The justfile loads the posthog public API key from the new .env
  • closes: https://github.com/open-sauced/pizza-cli/issues/125
  • Adds posthog capturing for codeowners generate commands and insight commands
• Introduces a just help command to get a list of all commands (and their descriptions)
  • closes: https://github.com/open-sauced/pizza-cli/issues/119
• Upgrades golangci-lint to golangci-lint:v1.60

Steps to QA

1. Build locally
2. For the core engineering team, you can log in and see the events being captured by the CLI

Tier (staff will fill in)

• [ ] Tier 1
• [ ] Tier 2
• [ ] Tier 3
• [x] Tier 4