Replaces local ChaCha20-Poly1305 with external crate

Migrates ChaCha20-Poly1305 encryption from the local crypto
module to rust-bitcoin's `chacha20-poly1305` crate.

Integrated the crate across all modules (Router,
PeerStorage, Onion Utils, etc.) and removed the deprecated internal
implementation. Updated test vectors to align with the new 12-byte
nonce construction and ensured SCID encryption remains consistent.

Author: Abeeujah

.github/workflows/build.yml

@@ -184,8 +184,8 @@ jobs:
           cargo doc --release
           cargo doc --no-default-features --release
         env:
-          RUSTFLAGS: '--cfg=taproot'
-          RUSTDOCFLAGS: '--cfg=taproot'
+          RUSTFLAGS: "--cfg=taproot"
+          RUSTDOCFLAGS: "--cfg=taproot"
 
   check_docs:
     runs-on: self-hosted
@@ -241,7 +241,7 @@ jobs:
       - name: Sanity check fuzz targets on Rust ${{ env.TOOLCHAIN }}
         run: |
           cd fuzz
-          RUSTFLAGS="--cfg=fuzzing --cfg=secp256k1_fuzz --cfg=hashes_fuzz" cargo test --verbose --color always --lib --bins -j8
+          RUSTFLAGS="--cfg=fuzzing --cfg=secp256k1_fuzz --cfg=hashes_fuzz --cfg=chacha20_poly1305_fuzz" cargo test --verbose --color always --lib --bins -j8
           cargo clean
       - name: Run fuzzers
         run: cd fuzz && ./ci-fuzz.sh && cd ..
@@ -307,7 +307,24 @@ jobs:
           TOR_PROXY="127.0.0.1:9050" RUSTFLAGS="--cfg=tor" cargo test --verbose --color always -p lightning-net-tokio
 
   notify-failure:
-    needs: [build-workspace, build-features, build-bindings, build-nostd, build-cfg-flags, build-sync, fuzz, linting, rustfmt, check_release, check_docs, benchmark, ext-test, tor-connect, coverage]
+    needs:
+      [
+        build-workspace,
+        build-features,
+        build-bindings,
+        build-nostd,
+        build-cfg-flags,
+        build-sync,
+        fuzz,
+        linting,
+        rustfmt,
+        check_release,
+        check_docs,
+        benchmark,
+        ext-test,
+        tor-connect,
+        coverage,
+      ]
     if: failure() && github.ref == 'refs/heads/main'
     runs-on: ubuntu-latest
     permissions:

lightning/Cargo.toml

@@ -41,6 +41,7 @@ lightning-macros = { version = "0.2", path = "../lightning-macros" }
 bech32 = { version = "0.11.0", default-features = false }
 bitcoin = { version = "0.32.4", default-features = false, features = ["secp-recovery"] }
 
+chacha20-poly1305 = { git = "https://github.com/Abeeujah/rust-bitcoin.git", rev = "fdf898d8651dd876fc36ee77da31350ed35349f9", default-features = false }
 dnssec-prover = { version = "0.6", default-features = false }
 hashbrown = { version = "0.13", default-features = false }
 possiblyrandom = { version = "0.2", path = "../possiblyrandom", default-features = false }