chore: remove Cursor-specific repository assumptions

[orbyteon]

Goal

Keep HOL build, validation and contribution guidance independent of the Cursor IDE/cloud environment.

Changes

• replace the Cursor Cloud-only AGENTS.md block with reproducible IDE-neutral Node, Unity and GitHub Actions guidance
• replace six historical cursor/...-291c branch assumptions with normal dated feature/... branch names
• ignore root-local .cursor/, .cursorrules, .cursorignore and .cursorindexingignore files

Scope

Documentation and .gitignore only. No Unity scenes, serialized assets, gameplay, networking, packages, workflows or production configuration changed.

Historical commit messages and pull-request bodies that mention Cursor are GitHub history/metadata, not project dependencies. Cursor Bugbot is an external GitHub App setting and is not configured in this repository tree.

Validation

• fetched and checked all 8 changed files from the branch
• zero active Cursor references remain outside the intentional .gitignore patterns
• zero cursor/... branch assumptions remain in the affected plans
• branch is 8 commits ahead / 0 behind its exact main base
• Unity was not run locally because no Unity source or serialized content changed; PR CI is the authoritative gate

[cursor]

Bugbot couldn't run - usage limit reached

Bugbot is counted against Cursor usage for this user or team, and this run hit a usage or spend limit.

A user or team admin can review and increase usage limits in the Cursor dashboard.

(requestId: serverGenReqId_28472441-35db-481a-8cb7-2a3364825ef5)

[orbyteon]

CTO stabilization hold: returned to draft to prevent AGENTS.md and workflow guidance from diverging while the canonical P0 architecture/CI contract is being repaired in PR #71. After stabilization, rebase and fold the IDE-neutral guidance into one canonical agent contract rather than maintaining competing instruction surfaces.

[orbyteon]

CTO integration hold (2026-08-26): this repository-guidance branch is preserved but returned to draft because it overlaps AGENTS.md/AI guidance changed by #72 and is based on an older main. After #72 lands, refresh from current main, retain only still-relevant changes, and rerun CI before review.