dgb(DC): AUX_DOGE merged-mining live-wire — embedded AuxChainEmbedded primary + RPC fallback (dual-target half)

[frstrtr]

DGB+DOGE merged-mining — DC live-wire (dual-target half)

Consumes the shared DOGE merged-mining seam to register DGB's own embedded AuxChainEmbedded backend as merged-mining primary, gated behind -DAUX_DOGE=ON. Phase DC of the D0->DE plan (frstrtr/the docs/dgb-doge-merged-mining.md).

Scope (3 fence checks)

1. AUX_DOGE OFF by default. Every new site is #ifdef AUX_DOGE; the DGB aux_chain_embedded.hpp header is self-guarded and compiles to nothing when off. Canonical LTC+DOGE path is untouched and non-consensus-bearing — the default-build legs (no AUX_DOGE) prove it.
2. SEPARATE deployment, distinct backend. This is DGB-as-parent with its own AuxChainEmbedded, NOT canonical LTC+DOGE. AuxPoW one-parent-per-DOGE-block holds: a DOGE block is merged under exactly one parent per deployment. chain_id and DOGE PREFIX/IDENTIFIER stay per-instance (isolation primitive, never unified).
3. Read-side interface consumption only. No writes into src/impl/doge internals — DGB registers through mm_manager->add_chain() / set_fallback_backend() and reads the shared module via the interface. src/impl/doge/coin/aux_* stays owned by ltc-doge.

Broadcaster invariant

submit_block() = P2P-relay primary via the manager-level block-relay fn (same route the DOGE embedded backend uses); digibyted RPC (AuxChainRPC) wired as never-removed fallback via set_fallback_backend(). Preserves the #82 dual-path gate under the AUX_DOGE build.

Files

• src/impl/dgb/coin/aux_chain_embedded.hpp — DGB embedded backend (self-guarded)
• src/impl/dgb/params.hpp — AUXPOW_CHAIN_ID + SubsidyFunc seam
• src/c2pool/c2pool_refactored.cpp — guarded registration block

No self-merge — TAP-GATED, awaiting operator tap after full rollup green.