Replace CONSTRAINTS.md with frontend-specific constraints - Next.js, SSR boundaries, UI philosophy, forbidden patterns

CONSTRAINTS.md

@@ -1,43 +1,43 @@
-# Constraints – zlh-grind
+# ZeroLagHub – Frontend Constraints (ZLH Grind)
 
-This repository is strictly for *decision tracking*, *constraints*, and *ground rules*.  
-It is not an implementation repo.
+These constraints are **non-negotiable**.  
+They exist to prevent architectural drift, instability, and "demo-ware" UI patterns.
 
----
+## Runtime & Framework
+- Node.js **22 LTS**
+- Next.js **App Router**
+- React 18
+- TypeScript
+- Build once → run many
+- No runtime builds
+- No PM2 during active development
 
-## Execution model constraints
-- zlh-agent executes installer logic as **embedded scripts**.
-- Embedded scripts must not rely on filesystem-relative paths (`$0`, `dirname`, etc.).
-- Any shared logic must be executed in the **same shell session** as its callers.
+## SSR & Client Boundaries
+- Any file that touches:
+  - `window`
+  - `document`
+  - `location`
+  - WebSockets
+  - xterm / DOM refs  
+  **MUST** be a client component with `"use client"` as the first line.
+- No browser globals at module scope in server components.
+- Prefer `useEffect` for browser-only logic.
 
----
+## UI Philosophy
+- Control-plane first, not marketing gimmicks.
+- Flat UI by default.
+- Subtlety beats spectacle.
+- Readability > novelty.
 
-## Installer contract constraints
-- Installers must be:
-  - deterministic
-  - artifact-driven
-  - idempotent
-  - strict (`set -euo pipefail`)
-- All runtime installers require explicit environment projection:
-  - `RUNTIME_VERSION` is mandatory
-  - artifact naming may be customized via `ARCHIVE_PREFIX`
-- Installers must not parse JSON or agent state files.
+## Explicitly Forbidden
+- Neon / RGB accent colors outside error states
+- Scanline / CRT / HUD overlays
+- Persistent 3D transforms or perspective UI
+- Excessive glow stacking
+- Clip-path bevel frames
+- Continuous decorative animations
 
----
-
-## Responsibility boundaries
-- API declares *intent* (runtime, version, container type).
-- Agent translates intent into:
-  - environment variables
-  - filesystem operations
-  - installer execution order
-- Installers perform no orchestration or decision-making.
-
----
-
-## Anti-patterns (explicitly forbidden)
-- Mega-installers that handle multiple runtimes via branching logic
-- Package-manager–based installs (apt, nvm, pyenv, sdkman)
-- Weakening installer strictness to accommodate agent bugs
-
----
+## Branding
+- Brand: **ZeroLagHub**
+- Shorthand: **ZLH**
+- Gaming heritage is acceptable, esports aesthetic is not.