Glyph-UTXO spend UX: auto-include fee-source input when spending dust Glyphs

[Zyrtnin]

Problem

Once #1 (Glyph-aware script parser) lands and the Send tab can spend Glyph UTXOs, there's still a UX cliff: Glyph UTXOs are typically dust-sized (1k–10k sats) while Radiant's min relay fee is 10,000 sats/byte. A 1-input 1-output tx spending a 10k-sat Glyph would need ~1.9M sats fee — impossible from the Glyph UTXO alone.

The Send flow needs to auto-select at least one additional fee-source UTXO from the same wallet when spending a Glyph.

Repro (will apply once #1 lands)

1. Wallet holds a Glyph UTXO worth 10,000 sats (0.0001 RXD)
2. User clicks the UTXO in Coins tab → Spend, destination = another address
3. Fee calculation says 1.9M sats minimum
4. Either the wallet errors out ("insufficient funds") or attempts to broadcast a tx that violates min relay

Fix (proposal)

In the coin-selection algorithm for Radiant sends:

1. If any selected input is a Glyph UTXO (i.e., its scriptPubKey matches the wrapped-P2PKH pattern from Script parser doesn't recognize Glyph-prefixed P2PKH — UTXOs invisible in GUI #1) AND the combined input value < tx_size × min_relay_rate, auto-add plain P2PKH UTXOs from the same wallet until the fee is covered.
2. Show a clear UI note: "This spend includes extra inputs to pay the network fee (0.03 RXD required). Change goes to [change_address]."
3. Optionally, warn: "This tx burns the Glyph NFT (ref not forwarded to any output). To transfer the Glyph instead, use Advanced → Transfer NFT." (v1.1 scope — forwarding the ref requires constructing a Glyph-carrying output, which is not today's scope.)

Privacy caveat worth surfacing in UI

Combining a Glyph UTXO with a plain P2PKH UTXO from the same wallet on-chain proves both belong to the same owner. If the Glyph came from a source with different provenance than the rest of the wallet (e.g., minted by a separate service), this combination breaks that privacy boundary. Consider a one-time warning on the first Glyph-spend send.

Scope clarification

• v1.1 (this issue): spend-and-burn — Glyph ref dropped, value returned to wallet as plain P2PKH change.
• v1.2+ (future): forward the Glyph — ref stays alive in an output that carries it to a new address.

Spend-and-burn matches the validated mainnet test: 22d4e0e07200….

Related

• Blocks on: Script parser doesn't recognize Glyph-prefixed P2PKH — UTXOs invisible in GUI #1 (script parser)
• Reference harness: spend_real_glyph_2in.py implements the 2-input spend logic end-to-end
• Doc: radiant-ledger-guide section 6 covers the fee-math rationale