fix(p2p): deduplicate host initialization

[matthewevans]

Summary by CodeRabbit

• Bug Fixes
  • Prevented multiplayer hosts from initializing more than once during the lobby-to-game transition.
  • Concurrent initialization requests now share the same setup process, reducing duplicate setup issues.
  • Failed initialization attempts can be retried automatically.

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Review details

⚙️ Run configuration

Configuration used: Path: .coderabbit.yaml

Review profile: CHILL

Plan: Pro Plus

Run ID: b3fcc146-6b57-49ae-ba80-c56b936168e5

📥 Commits

Reviewing files that changed from the base of the PR and between f5f5338 and fb298a7.

📒 Files selected for processing (2)

• client/src/adapter/__tests__/p2p-adapter-multiplayer.test.ts
• client/src/adapter/p2p-adapter.ts

📝 Walkthrough

Walkthrough

P2PHostAdapter initialization now runs once across concurrent and repeated calls, retries after failure, and has a regression test covering lobby-to-game handoff behavior.

Changes

P2P host initialization

Layer / File(s)	Summary
Run-once initialization guard client/src/adapter/p2p-adapter.ts, client/src/adapter/__tests__/p2p-adapter-multiplayer.test.ts	P2PHostAdapter shares in-flight initialization, skips completed setup, clears failed promises for retries, marks successful initialization, and verifies that setup and multiplayer mode changes occur once.

Estimated code review effort: 2 (Simple) | ~10 minutes

Possibly related PRs

• phase-rs/phase#6614: Updates game-store adapter assignment ordering for the related P2P startup handoff race.

Suggested reviewers: minion1227

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 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: preventing duplicate host initialization in P2P.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
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.

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch ship/fixp2p-deduplicate-host-initialization

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[coderabbitai]

Actionable comments posted: 2

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Inline comments:
In `@client/src/adapter/__tests__/p2p-adapter-multiplayer.test.ts`:
- Around line 410-418: Add a test alongside the existing host initialization
test that makes the first initialize attempt reject, verifies a subsequent
initialize succeeds, and then simulates a guest connection to assert it is
accepted exactly once. Exercise the retry through the adapter’s initialization
flow and verify failed initialization does not leave duplicate listeners or
otherwise prevent the successful retry.

In `@client/src/adapter/p2p-adapter.ts`:
- Around line 1105-1111: Make initialize and initializeInner retry-safe:
preserve single-flight behavior for concurrent callers, but reset or recreate
the constructor-owned pregameReady gate after a failed attempt so a later
successful retry can resolve it. Ensure each failed attempt removes its
onGuestConnected subscription before clearing initPromise and permitting another
retry, preventing duplicate guest processing.

🪄 Autofix (Beta)

Fix all unresolved CodeRabbit comments on this PR:

• Push a commit to this branch (recommended)
• Create a new PR with the fixes

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ℹ️ Review info

⚙️ Run configuration

Configuration used: Path: .coderabbit.yaml

Review profile: CHILL

Plan: Pro Plus

Run ID: 1bb96475-8d61-4d3d-926f-32f8614c6295

📥 Commits

Reviewing files that changed from the base of the PR and between 616d5fd and f5f5338.

📒 Files selected for processing (2)

• client/src/adapter/__tests__/p2p-adapter-multiplayer.test.ts
• client/src/adapter/p2p-adapter.ts