Merge branch 'master' into next

Forward-merge the v0.4.0 pre-release content (dependency refresh, CI
deb-install + AUR-build legs, docs refresh, doc-comment fixes, and the
Phase 4 source-content squash: CHANGELOG, release notes, README,
fips.yaml, Cargo.toml metadata, reference docs) up the one-way flow.

Conflict fixups (keep next's identity, fold in master's improvements):
- Version: keep next's 0.5.0-dev (Cargo.toml/lock).
- README status: keep next's v0.5.0-dev / wire-format-breaking framing
  and the Breaking-section pointer; fold in the Nym transport and the
  "global, public test mesh of thousands of nodes" description.
- docs/reference/cli-fips.md: keep next's 0.5.0-dev version example.
- CHANGELOG: keep next's XX-handshake admission entry (no early cap gate
  on XX) and drop master's IK early-cap-at-handle_msg1 entry, which
  describes IK-only behavior that does not apply on next; take master's
  OR-union mesh-size rewrite (next carries the OR-union code); restore
  the Tor connect_refused and MMP receiver-report entries that the
  Fixed-section consolidation would otherwise have dropped.
- lifecycle.rs: keep the mDNS/LAN handshake doc-comment as Noise XX
  (next unifies on XX), not master's XX-to-IK correction.

Quartet green on the merged tree: fmt, build, clippy -D warnings, and
cargo test --lib (1434 passed).

.github/workflows/ci.yml

@@ -40,9 +40,9 @@ env:
 #
 # Granularity-only differences (same coverage, different matrix shape —
 # NOT a divergence):
-#   deb-install    — split here into per-distro legs (debian12/ubuntu24/
-#                    ubuntu26) for parallelism; local runs all distros in one
-#                    suite.
+#   deb-install    — split here into per-distro legs (debian12/debian13/
+#                    ubuntu22/ubuntu24/ubuntu26) for parallelism; local runs the
+#                    same distro set in one suite.
 #   dns-resolver   — single leg here; runs all scenarios (same as local).
 # ─────────────────────────────────────────────────────────────────────────────
 
@@ -457,6 +457,12 @@ jobs:
           - suite: deb-install-debian12
             type: deb-install
             scenario: debian12
+          - suite: deb-install-debian13
+            type: deb-install
+            scenario: debian13
+          - suite: deb-install-ubuntu22
+            type: deb-install
+            scenario: ubuntu22
           - suite: deb-install-ubuntu24
             type: deb-install
             scenario: ubuntu24