CLI: Cepha Store ظ€¤ version-locked premium acquisition system

[sultanaalyami]

Implemented

Cepha Store ظ�¤ Version-Locked Premium Acquisition System

Architecture:

• ~/.cepha/store/store.db ظ�¤ SQLite registry of all acquisitions
• ~/.cepha/store/packages/{featureId}/{cliVersion}/ ظ�¤ versioned package storage
• Each package has manifest.json (metadata + SHA-256 hash) + payload/ directory

Key Invariant: A store-acquired package is version-locked to the CLI version that installed it. Packages for v1.0.52 will not load on v1.0.53. This follows Microsoft's immutable store pattern.

Security:

• SHA-256 per-file content hashing
• Combined directory hash (path + content)
• Tamper detection via cepha store verify
• Integrity timestamp tracking

CLI Commands:

Command	Description
cepha store	Browse premium catalog with install status
cepha store list	Show installed packages (current version only)
cepha store verify [id]	Verify integrity of one or all packages
cepha store info <id>	Show detailed package & license info
cepha store history	Show acquisitions across ALL CLI versions
cepha store uninstall <id>	Remove a package

Integration:

• CephaLicense.IsEnabled() checks store acquisitions first
• CephaLicense.GetStatusLabel() shows store status with version info
• Store menu added to InteractiveMenu (position 13)
• cepha store registered as CLI command in Program.cs

Files: CephaStore.cs (569 lines), StoreCommand.cs (465 lines)

Migrated from: WasmMvcRuntime #40