feat(aidd-context): restore startup greeting with installed framework version #980

Objective

Restore the first-message greeting and make the installed AIDD framework version visible, encouraging users to discover newer releases and upgrade.

Proposed behavior

Show once per new conversation:

AI-Driven Development On ⚡ · Framework v · Releases

Use the locally installed framework version, without a network request. If unavailable, show Framework version unknown. Restore the rule in the project-memory template so generated context files include it.

Benefits and limits

• Makes the installed version and available releases easy to find.
• Version metadata must stay current after upgrades.
• The framework version does not describe every independently versioned plugin.

Acceptance criteria

• A fresh conversation displays the greeting once, with the releases link.
• The version matches the local framework installation, or explicitly reads unknown.
• After upgrading, a new conversation displays the updated version.
• Verified in Claude Code and Codex.