build: prepare 0.2.2 against delivery_module v0.2.0

[igor-sirotin]

Summary

delivery_module v0.2.0 is tagged and about to enter logos-modules-release, so this module moves its pin from v0.1.3 to the release it will be installed alongside:

• flake.nix: logos-delivery-module re-pinned v0.1.3 → v0.2.0, lock refreshed.
• rust-lib/deps/delivery_module.lidl: the hand-maintained contract copy's version moves to 0.2.0. The subset chat_module consumes (createNode/start/subscribe/send + the messageReceived/connectionStateChanged decoders) is unchanged in v0.2.0. Switching to the published .lidl output that v0.2.0 now ships stays build: consume delivery_module's published .lidl contract #58's scope.
• createNode config moves to the layered app-developer shape ({"mode", "preset", "messagingOverrides": {"logLevel"}}). v0.2.0 no longer injects port 0 for unpinned ports (delivery-module#79: the injected top-level keys forced every config through the legacy flat parser and broke the layered shapes). Our old config was flat-shaped too — the top-level logLevel is a bare kernel key — so side-by-side instances all bound the fixed default tcp/60000 (SO_REUSEPORT lets the extra binds land silently), announced the same address under different peer ids, and exchanges never completed (evidence: chat-ui e2e run against the first commit). The layered shape routes through the messaging layer, which defaults every unpinned port to 0 (OS-assigned).
• Version bumped to 0.2.2: 0.2.1 is tagged and released against delivery v0.1.3, so the work since it gets a version of its own to be released under.

Testing

• cargo fmt --check, cargo clippy -D warnings, cargo test (32 passed) and nix build .#chat_module locally.
• logos-chat-ui's standalone app builds against this rev end to end (companion: build: prepare 0.2.2 against chat_module 0.2.2 / delivery_module v0.2.0 logos-chat-ui#54).
• The doc-tests on this PR drive the real 1:1 and group exchanges with the v0.2.0 delivery_module-lgx re-exported from this flake — they run several instances on one host, so they exercise the port auto-assignment directly.

🤖 Generated with Claude Code

[github-actions]

Doc-test report

Headless chat_module instances built against this commit, driven through the 1:1 round-trip and the three-instance group conversation, rendered alongside the commands actually run and their output (updated each run, commit c0c7252):

• Execution report

Pages can take a minute to update after the run finishes.

[igor-sirotin]

This is the only API call change