feat: expand ENHO, INCL, and Dynpro support

[Augusto42]

What changed

• adds read-only ENHO discovery, source fallback, attached-enhancement lookup, merged include views, and enhancement-aware grep
• adds first-class INCL create and update through the safe unified source workflow
• adds experimental read-only DYNP metadata, layout, and flow-logic retrieval through ZADT_VSP and RPY_DYNPRO_READ
• documents operation-level object support and explicit unsupported mutation paths

Why

Classic includes, enhancement implementations, and Dynpro screens are important in ECC and on-premise maintenance work, but the unified API either lacked these paths or could only read part of the object graph. This change expands useful coverage without presenting unvalidated classic mutations as safe.

Safety and compatibility

• Dynpro remains read-only; create, update, and delete are intentionally unavailable pending non-production SAP validation
• INCL uses SyntaxCheck, Lock, UpdateSource, Unlock, and Activate in that order
• program include URLs are no longer mistaken for OO class include URLs
• existing APC services and MoveObject behavior are preserved
• public fixtures and examples use synthetic identifiers only
• ENHO work incorporates upstream PR feat(adt): SAP Enhancement Framework (ENHO) read support oisee/vibing-steampunk#130 while preserving the original commit authorship

Validation

• CGO_ENABLED=0 go vet ./...
• CGO_ENABLED=0 go test ./... -count=1
• CGO_ENABLED=0 go build ./cmd/vsp
• git diff --check