feat(topology): Map SwiftPM targets

[reneleonhardt]

What does this PR do?

Adds SwiftPM target topology discovery from Package.swift:

• Parses package products, targets, target paths, and declared target dependencies.
• Resolves target paths conservatively into the typed topology graph.
• Keeps malformed or ambiguous declarations bounded and unresolved.

Why it matters

Swift packages define module boundaries and dependencies in Package.swift; directory-only topology misses that structure.

CLI / MCP surface

No new commands, arguments, or MCP tools. Existing topology output includes SwiftPM package and target nodes.

Security

Package.swift is parsed as source text and never executed.

Review follow-ups included

• Ignores package-shaped syntax inside normal, raw, and multiline Swift strings.
• Rejects computed or interpolated target values while accepting escaped delimiters and literal string forms.

Verification

• codemap . and codemap --deps .

Co-Authored-By: GPT-5.6 Sol codex@openai.com