Open and accept zero reserve channels#4428

Draft

tankyleo wants to merge 22 commits intolightningdevkit:mainfrom

tankyleo:2026-02-zero-reserve

Commits on Feb 5, 2026

Simplify calculation of the biggest HTLC value that can be sent next
tankyleo
committed

Commits on Feb 16, 2026

Commits on Feb 18, 2026

f: Remove debug assert on `addl_nondust_htlc_count`
tankyleo
committed
Delete `TxBuilder::subtract_non_htlc_outputs`
tankyleo
committed
Create `ChannelConstraints` to hold parameters for balance calculations
tankyleo
committed
Extract dust exposure calculation in `tx_builder` to its own function
tankyleo
committed
Rewrite `get_available_balances_for_scope` using `tx_builder` functions
tankyleo
committed
Move `ChannelContext::get_available_balances_for_scope` to `tx_builder`
tankyleo
committed
Format `tx_builder::get_available_balances`
tankyleo
committed
f: Explain why we take remote's view of pending HTLCs on `get_available_balances`
tankyleo
committed
Multiply the feerate by the spike multiple in `can_accept_incoming_htlc`
tankyleo
committed
Erase `get_pending_htlc_stats`, `next_*_commit_tx_fee_msat` in `channel`
tankyleo
committed
Return `AvailableBalances` in `get_onchain_stats`
tankyleo
committed
Unwrap `get_available_balances` with no counterparty unknown HTLCs
tankyleo
committed
fixup: Add a fallback in release mode
tankyleo
committed