feat(nakama): add reincarnation placeholder

[JOY (JOY)]

Summary

• Add secondspawn_reincarnate as the prototype death to fresh-body flow after BodyTime reaches zero.
• Seed prototype accounts with a 7-day SECOND test balance and charge a 5-day SECOND reincarnation cost.
• Reset the current body into a fresh prototype body while preserving durable soul, memory, traits, policy, runtime counters, and activity history.
• Add idempotent reincarnation retry handling through activity IDs, block reincarnation for living bodies, and block reincarnation when SECOND balance is insufficient.
• Expose SECOND balance, reincarnation count, and a Unity Nakama reincarnation wrapper.

Verification

• npm run build in backend/nakama
• npm test in backend/nakama
• go test -count=1 ./... in backend/gateway
• go vet ./... in backend/gateway
• npx --yes markdownlint-cli2@0.18.1 "*.md" "docs/**/*.md" ".github/**/*.md"
• git diff --check
• Changed-file em-dash/en-dash scan

Local Review

Local code-review skill pass result: approved with suggestions. No engine specialist is configured in .Codex/docs/technical-preferences.md, so specialist routing was skipped. This keeps the placeholder in Nakama runtime per ADR 0010 and keeps SECOND distinct from current-body BodyTime.

Caveat

Unity clean-worktree batchmode compile is still blocked by the existing Package Manager path undefined issue in this repo family, so Editor/MCP compile verification remains required before a no-caveat Unity merge claim.

Gemini (@gemini-code-assist) review
Codex (@codex) review

[gemini-code-assist]

Warning

You have reached your daily quota limit. Please wait up to 24 hours and I will start processing your requests again!

[chatgpt-codex-connector]

You have reached your Codex usage limits for code reviews. You can see your limits in the Codex usage dashboard.

[JOY (JOY)]

Local delta review after rebase onto current dev:

• Rebased after BodyTime (feat(nakama): add BodyTime event flow #15) and cultivation deferral (chore: defer cultivation progression #18).
• Preserved the reincarnation placeholder flow while removing all cultivation/progress_xp carryover from runtime contracts.
• Checked idempotent reincarnation retries, alive-body rejection, insufficient SECOND balance rejection, body reset, activity logging, and memory carryover in Nakama tests.
• Runtime grep is clean for cultivation, Nibirium, progress_xp, and CultivationTier under backend/ and Unity/Assets/_SecondSpawn/Scripts.
• Reviewer bots are quota-limited, so this is the local code-review fallback.

Verification:

• npm run build && npm test in backend/nakama
• go test -count=1 ./... && go vet ./... in backend/gateway
• markdownlint-cli2
• git diff --check
• runtime grep for removed cultivation terms

Verdict: APPROVED for merge into dev if CI remains green.

[JOY (JOY)]

Local delta review after rebase onto dev:

• Rebased reincarnation placeholder on top of merged BodyTime and cultivation-defer decisions.
• Verified the reincarnation runtime no longer carries cultivation, Nibirium, progress_xp, or CultivationTier fields.
• Reviewed the server boundary: reincarnation requires a dead body, enough SECOND balance, and server-side RPC execution. Clients and LLMs still cannot mutate authoritative state directly.
• Checked idempotency: retrying the same reincarnation id does not spend SECOND or increment count twice.
• Checked zero-time flow: BodyTime drain kills the body, reincarnation creates a fresh body, restores prototype BodyTime, records activity, carries soul, memory, policy, and traits, and spends prototype SECOND.

Verification:

• npm run build && npm test in backend/nakama
• go test -count=1 ./... && go vet ./... in backend/gateway
• markdownlint-cli2
• git diff --check
• runtime grep for cultivation, Nibirium, progress_xp, CultivationTier, and em/en dash

Verdict: APPROVED for merge into dev.