Rest-surface stage has no cross-bucket occupancy dedup: PC and stage_cell'd NPC can share a cell in direct seeds

[100yenadmin]

Found during #1639/#1662 (viewer _scene_stage): in a DIRECT current-room seed, the PC (no seeded stage_cell) and a stage_cell'd NPC can land on the SAME cell (measured: Maera+Aidan both at (5,3) in tavern_snug). Pre-existing on main, not introduced by #1662. During a real walk the PC gets a unique arrival cell from _seed_stage_cells_on_arrival, so it only bites fresh/direct seeds — i.e. a brand-new campaign could open with the party standing inside the quest-giver. Fix shape: occupancy-aware placement across the party/NPC/foe buckets in _scene_stage (or at seed time), mirroring the arrival-cell uniqueness rule. Evidence: /Volumes/LEXAR/Codex/session-notes/2026-07-22/cast-presence-1639/artifacts/live_curl_proof.txt

[evaos-code-review-bot]

evaOS issue enrichment

Issue: #1663 - Rest-surface stage has no cross-bucket occupancy dedup: PC and stage_cell'd NPC can share a cell in direct seeds
State: open

Related issues/PRs: #1639, #1662.
Existing labels: none.
Suggested labels: none.
Suggested owners: none.

Related context

• Walked world renders empty of its cast: rest-surface tokens exclude NPCs + spawned monsters (first A-G weakest-link finding) #1639 - mentioned in issue metadata; inspect for dependency, duplicate, or prior-decision risk.
• engine: rest surface emits located cast (NPCs + live monsters) — closes #1639 #1662 - mentioned in issue metadata; inspect for dependency, duplicate, or prior-decision risk.

Agent-start packet

Problem shape: Rest-surface stage has no cross-bucket occupancy dedup: PC and stage_cell'd NPC can share a cell in direct seeds - Found during #1639/#1662 (viewer _scene_stage): in a DIRECT current-room seed, the PC (no seeded stage_cell) and a stage_cell'd NPC can land on the SAME cell (measured: Maera+Aidan both at (5,3) in tavern_snug).
Product fit: Implementation issue; keep product fit lightweight unless VISION.md/repo policy raises a constraint.
Implementation wedge: Start with a focused fixture or dry-run path that proves the issue shape before widening behavior.

Build / borrow / buy scan:

• Build: identify the smallest implementation wedge that proves the issue without broad rollout.
• Borrow: inspect same-repo prior art, repo memory, GitNexus context, and allowlisted cross-repo examples first.
• Buy/use: deferred; no product, architecture, UX, library-choice, integration, roadmap, or market-positioning trigger detected.

Candidate sources:

• VISION.md / repo policy / repo-memory.md / GitNexus packet.
• Same-repo issues and PRs referenced by issue metadata.

Acceptance criteria:

• Add explicit acceptance criteria before implementation is considered done.
• Include source citations for any external OSS/library/current-market claims.
• Keep issue-enrichment comments sticky and idempotent.
• Keep labels, owners, reviewers, and roadmap fields suggestion-only.

Proof plan:

• Focused unit/fixture test for the changed planner behavior.
• Dry-run issue-enrichment evidence packet before live comment posting.
• Redaction check for issue body, citations, and generated markdown.

Known traps:

• Do not treat related links as proof by themselves; each source needs a reason why it matters.
• Do not scan old issue backlogs or exceed repo-level enrichment throttles.

Non-goals:

• Do not auto-apply labels, owners, reviewers, roadmap fields, or milestones.
• Do not bulk-enrich old backlog issues from this planner output.
• Do not claim external market or OSS research was performed unless cited sources are present.

Context-source taxonomy:

• [enabled] vision_repo_policy_memory_gitnexus: Use repo vision, policy, memory, and GitNexus first before external research.
• [enabled] same_repo_issues_prs: Issue metadata contains same-repo references.
• [deferred] allowlisted_cross_repo_github: Deferred until product, UX, market-positioning, or library-choice signal appears.
• [deferred] external_oss_examples: Deferred for low-research-value issue class.
• [deferred] library_api_docs: Deferred unless a library/API decision is present.
• [deferred] current_market_examples: Deferred for implementation-only issues.
• [enabled] internal_mcp_docs: Use internal docs/MCP context when available; missing context is degraded, not blocking.

Validation suggestions

• Confirm owner, acceptance criteria, and validation evidence before implementation.

Triage gaps

• Acceptance criteria or validation evidence not detected in issue body.
• Owner or reviewer signal not detected in issue body.

No labels, owners, reviewers, or roadmap fields were changed by this bot.