fix(reader): attach metadata to read-string collections

[nnunley]

Summary

• add an explicit per-reader data mode for compiler.ReadString, read-string, and read-all-string
• attach metadata directly to map, list, vector, and set values while preserving compiler-reader (with-meta ...) forms
• preserve raw symbol type hints in attached collection metadata; metadata-bearing symbol targets remain deferred
• return real sets in data mode without changing compiler set-form representation
• accept metadata-promoted persistent vectors in deps.edn consumers (resolver and lginterop)

Stack and scope

Depends on #770 and must merge after it. This draft currently contains #770's commit plus this change; after #770 merges it should be rebased onto main before review/merge.

This addresses only the metadata section of #801. It intentionally does not close #801: map-interior #_ discard handling remains open.

Validation

• go test ./pkg/compiler ./pkg/resolver ./cmd/lginterop
• focused go test -race across metadata, tagged-reader, resolver, and lginterop regressions
• go vet ./pkg/compiler ./pkg/resolver ./cmd/lginterop
• make generate
• make check-generated
• all ./pkg/... packages except the sandbox-contaminated pkg/genmanifest oracle, plus all ./cmd/...
• independent review; one persistent-vector config compatibility finding fixed; re-review passed

Local go test ./... remains unavailable in this sandbox because existing tests write literal /tmp paths and the read-only global module cache emits stderr into a JSON oracle. CI is required for the unrestricted repository-wide gate.

Relates to #801.