Preserve unrepresentable raw action values as references

[sfly9]

Summary

Decompiling a raw action parameter whose value doesn't match any shape decompValueObject knows how to represent (e.g. a third-party app's opaque struct, such as a HomeKit scene selection) currently produces a silent empty string — the underlying data is discarded with no indication anything was lost. I hit this decompiling a Shortcut that uses a HomeKit trigger action.

This routes those values through the existing #ref mechanism instead of discarding them:

• decompile.go: when decompValueObject can't represent a raw action parameter, register the value as a reference and emit a ${identifier} placeholder in the rawAction dict, with a decompWarning (existing helper, same pattern as the one at decompile.go:1186) noting a reference was substituted. Handles naming collisions when the same parameter key produces different values across multiple actions in the same Shortcut.
• raw_actions.go: ${...} placeholders inside a rawAction() dict now also resolve against declared #refs (only when there's no @, since variable references always use @), not just variable names.
• references.go: reference hashes now survive raw []byte (plist <data>) values. JSON has no native binary type, so without this a <data> element would silently round-trip back as an indistinguishable <string> — a correctness bug in the existing file/media reference path that this change also happens to fix, even though those reference types don't currently carry byte data.

Testing

• go build ./...
• go test -run TestCherriNoSign and go test -run TestDecomp — pass, including the new test case
• golangci-lint run ./... — 22 pre-existing findings, confirmed identical (same count, same lines) on unmodified main; this change introduces none
• Added a case to tests/raw-action-variable-values.cherri exercising a #ref used inside a rawAction() dict (the #ref hash was generated by the compiler itself against a synthetic fixture, not hand-written)
• Manually verified against a real Shortcut using a HomeKit trigger action: recompiled the decompiled output and diffed the resulting plist's parameter value against the original — byte-for-byte identical, including the binary payload