Allow verify to target manifest kinds

[kriptoburak]

Summary:

• Let asrpm verify --target select an explicit manifest target kind, while keeping install limited to the supported Claude Code path.
• Add helper and verifier tests for explicit target-kind verification.
• Document verify in the README command tree and replace stale EIP draft links with the reachable protocol repository.

Validation:

• gofmt -l internal/commands/install.go internal/commands/install_helpers_test.go internal/commands/verify.go internal/commands/verify_test.go internal/commands/help.go
• go test ./...
• go vet ./...
• npx --yes markdown-link-check README.md
• git diff --check

Note:

• Repo-wide gofmt -l . still reports the pre-existing internal/commands/resolve_helpers_test.go; this PR does not touch that file.