Implement typed merge, bind, occurrences, paint, split, and group options

## Parent

- #7

## What to build

Implement typed collection transformations on RFC-0003 Values, RollSet references, immutable instruction history, and trace DAGs.

## Frozen contract

- `m(expr)` combines explicit compatible collections and produces a `merge` trace node; bare `m` is invalid.
- `b` reads compatible completed instruction values, records `source_instruction_ids`, and never mutates ProgramResult history.
- `o` / `o(N,S)` returns ordered nested `[value, count]` Values with occurrence provenance.
- `p[color:N,...]` changes RollSet-view annotations and emits paint assignments without mutating RollNodes.
- `y` flattens one Values level or spreads compound draws while keeping node IDs.
- `gN` creates consecutive width-N nested Values with a final short remainder.

## Acceptance criteria

- [ ] Every option matches RFC-0001 input/output and cardinality cases.
- [ ] Merge/bind preserve instruction IDs, trace inputs, and source-node identity.
- [ ] Occurrence order, selectors, paint normalization, split depth, and group remainder are deterministic.
- [ ] Empty RollSets retain `item_kind`; annotations do not alter scalar projection.
- [ ] Wrong-kind, zero, oversized, forward-bind, and incompatible requests return spanned RFC-0003 errors.
- [ ] Rust, installed Python, CLI JSON, and docs agree on schema-valid output.

## Blocked by

- #7
- #4
- #12
- #15
- #21
- #39
- #41

Read RFC-0001 and RFC-0003 first, then inspect the blocked issues #7, #4, #12, #15, #21, #39, and #41 for prerequisite behavior and schemas. Validate the implementation through the Rust, installed-Python, CLI JSON, and documentation paths; done means all listed options satisfy the frozen contract, deterministic cases, error handling, and schema agreement.

Written by the indexing model from the issue text.