feat(protocol): apply v2 first-contact PoW on NewOrder and take actions

[arkanoider]

Summary

Protocol v2 step 8: Mostro daemons can require higher PoW for first contact from unseen trade keys (NewOrder, TakeBuy, TakeSell). Mostrix now mirrors the daemon’s max(pow, pow_first_contact) rule on v2 outbound protocol DMs.

Part of the protocol v2 NIP-44 migration (follows #90).

Changes

• Parse optional pow_first_contact from kind 38385 into MostroInstanceInfo
• Add effective_pow_first_contact_from_instance, is_v2_first_contact_protocol_action, and nostr_pow_for_protocol_dm
• send_dm uses per-action PoW via nostr_pow_for_protocol_dm instead of base nostr_pow_from_instance
• Mostro Info tab shows “Required PoW (first contact, v2)” when the tag is present
• Docs: POW_AND_OUTBOUND_EVENTS.md, MESSAGE_FLOW_AND_PROTOCOL.md
• Unit tests for tag parsing and v1/v2 PoW selection

Summary by CodeRabbit

• New Features

  • UI now displays first-contact Proof-of-Work (PoW) requirements separately when available on v2 protocol nodes
  • Direct message protocol now correctly applies the maximum required Proof-of-Work difficulty for first-contact protocol actions on v2 nodes

• Documentation

  • Updated Proof-of-Work and outbound message flow documentation to reflect new first-contact requirements, v2 node behavior, and how difficulty levels are determined and applied

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro

Run ID: 283dbe77-e118-4a3c-899f-8a7ae436d321

📥 Commits

Reviewing files that changed from the base of the PR and between 3926277 and e0da08d.

📒 Files selected for processing (5)

• docs/MESSAGE_FLOW_AND_PROTOCOL.md
• docs/POW_AND_OUTBOUND_EVENTS.md
• src/ui/tabs/mostro_info_tab.rs
• src/util/dm_utils/mod.rs
• src/util/mostro_info.rs

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Walkthrough

Adds pow_first_contact: Option<u32> to MostroInstanceInfo, parses it from kind 38385 tags, and introduces effective_pow_first_contact_from_instance and is_v2_first_contact_protocol_action. nostr_pow_for_protocol_dm applies max(pow, pow_first_contact) for v2 direct transport on first-contact actions. send_dm now deserializes the payload before computing PoW. The UI and docs are updated accordingly.

Changes

pow_first_contact support for v2 first-contact actions

Layer / File(s)	Summary
MostroInstanceInfo field, tag parsing, PoW utilities, and tests src/util/mostro_info.rs	MostroInstanceInfo gains pow_first_contact: Option<u32>; mostro_info_from_tags parses the new tag; nostr_pow_from_instance is refactored with a clamping helper; effective_pow_first_contact_from_instance and is_v2_first_contact_protocol_action are introduced; nostr_pow_for_protocol_dm applies max(base, first_contact) for v2 Nip44Direct transport on NewOrder, TakeBuy, and TakeSell; tests cover all new and fallback paths.
send_dm PoW import and ordering update src/util/dm_utils/mod.rs	Imports nostr_pow_for_protocol_dm instead of nostr_pow_from_instance; send_dm now deserializes payload into a Message first, then derives PoW using the parsed action via nostr_pow_for_protocol_dm.
UI display and documentation updates src/ui/tabs/mostro_info_tab.rs, docs/MESSAGE_FLOW_AND_PROTOCOL.md, docs/POW_AND_OUTBOUND_EVENTS.md	build_info_lines conditionally renders a "Required PoW (first contact, v2)" row when pow_first_contact is present; both docs files updated to document the max(pow, pow_first_contact) rule and the pow_first_contact tag in kind 38385.

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~20 minutes

Possibly related PRs

• MostroP2P/mostrix#51: Introduced nostr_pow_from_instance and the initial instance-derived PoW plumbing that this PR extends with pow_first_contact and nostr_pow_for_protocol_dm.
• MostroP2P/mostrix#86: Also extends MostroInstanceInfo and kind 38385 tag parsing in src/util/mostro_info.rs, adding protocol_version and transport_from_instance.
• MostroP2P/mostrix#88: Modifies the same send_dm function in src/util/dm_utils/mod.rs for protocol v2, refactoring transport wrapping and v2 default expiration.

Poem

🐇 Hop hop, the first contact toll now stands clear,
A pow_first_contact tag makes the rule appear.
For v2 direct sends, we take the max of two,
No more guessing—just max(pow, pow_first_contact) will do!
The daemon and Mostrix now speak the same tongue,
This rabbit is proud of the code that was flung. 🌟

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title accurately summarizes the main change: implementing v2 first-contact PoW on NewOrder and take actions, which aligns with the PR's primary objective of enabling higher PoW requirements for first-contact messages.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

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✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch feat/protocol-v2-pow-first-contact

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[mostronatorcoder]

I did a strict pass on this PR and I do not currently see a correctness blocker.

What I specifically checked:

• pow_first_contact parsing from instance info
• the fallback semantics in effective_pow_first_contact_from_instance()
• the v1/v2/action gating in nostr_pow_for_protocol_dm()
• the send_dm() integration point, to make sure the higher toll is derived from the actual inner action being wrapped

This looks coherent to me.

In particular, I like that the rule is not “always use pow_first_contact on v2”, but only for the first-contact protocol actions (NewOrder, TakeBuy, TakeSell), while other actions stay on base pow. That matches the daemon-side intent much better than a blanket increase would.

So from my side this looks like a good step 8: small surface area, correct scope, and a clean mirror of the daemon’s effective PoW rule for first-contact v2 traffic.

[ermeme]

Code Review Summary

Verdict: Approve

Looks good overall. The new first-contact PoW handling matches the v2 protocol flow, the parser and UI updates are consistent, and the new tests cover the added branches.