T-1: Introduce ProjectID canonical identity value type

[kirich1409]

Part of EPIC #193.

Description

Introduce a ProjectID value type in MacApp/Packages/SharedModels/Sources/SharedModels/ProjectID.swift, wrapping a canonical absolute path string. Canonicalization: URL(fileURLWithPath:).resolvingSymlinksInPath().standardizedFileURL.path. Handles edge cases: ~/, trailing slash, symlinks, relative paths.

Acceptance Criteria

• ProjectID is a public struct conforming to Hashable, Codable, Sendable, Equatable, CustomStringConvertible
• Public constructors: init(url: URL), init?(path: String) (nil for empty / invalid)
• Canonicalization: ~/foo, /Users/me/foo/, and a symlink to /Users/me/foo all produce the same ProjectID
• Unit tests cover: symlink resolution, trailing slash normalization, ~/ expansion, empty / invalid string, APFS case sensitivity
• Public rawValue: String for serialization
• Build passes, swiftlint lint --strict clean, all existing tests pass

Module / Layer

SharedModels / Domain

Complexity

Small