Add BOLT12 support to LSPS2 flow#817

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tnull wants to merge 5 commits intolightningdevkit:mainfrom

tnull:2026-03-lsps2-bolt12-router-integration

Commits on Apr 2, 2026

WIP: Add LSPS2-backed BOLT12 JIT offer routing
tnull
committed

Commits on Apr 7, 2026

Commits on Apr 8, 2026

f - Use `u16` for LSPS2 `cltv_expiry_delta` and update rust-lightning rev
tnull
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