## 1. Go Runtime Baselines

- [x] 1.1 Add an independent Go module under `platform/` with minimal command, config, HTTP health surface, and tests.
- [x] 1.2 Add an independent Go module under `run/` with minimal command, config, platform client boundary, smoke-test mode, and tests.
- [x] 1.3 Verify neither Go module imports implementation code from another project root.

## 2. Platform Web Baseline

- [x] 2.1 Add npm, Vite, React, and TypeScript baseline files under `platform_web/`.
- [x] 2.2 Add route definitions, API client boundaries, required page placeholders, shared components, theme tokens, and test setup in the required directories.
- [x] 2.3 Add scripts for `dev`, `build`, `typecheck`, `test`, and `preview`.

## 3. Plugin Workspace Baseline

- [x] 3.1 Add npm and TypeScript baseline files under `plugins/`.
- [x] 3.2 Add SDK export stubs, schema validation scripts, example manifest validation, and tests inside the plugin root.
- [x] 3.3 Keep plugin checks scoped to plugin contracts and do not add platform marketplace behavior in this change.

## 4. Root Orchestration And Documentation

- [x] 4.1 Add a root verification script that runs structure checks plus each root's baseline checks without containing application logic.
- [x] 4.2 Update `scripts/check-structure.sh` for new required baseline files and directories.
- [x] 4.3 Update root and per-root README files with tool versions, dependency install commands, local start commands, verification commands, and baseline scope limits.

## 5. Verification

- [x] 5.1 Run `go test ./...` in `platform/`.
- [x] 5.2 Run `go test ./...` in `run/`.
- [x] 5.3 Run the documented install, typecheck, test, and build commands in `platform_web/`.
- [x] 5.4 Run the documented install, typecheck, test, and schema validation commands in `plugins/`.
- [x] 5.5 Run the root full-check script and `scripts/check-structure.sh`.
- [x] 5.6 Start the platform_web dev server and complete a browser walkthrough at desktop and mobile widths.
- [x] 5.7 Run `openspec validate establish-development-runtime-baseline --strict`.

## Evidence

- `go test ./...` in `platform/`: passed.
- `go test ./...` in `run/`: passed.
- `npm install`, `npm run typecheck`, `npm run test`, and `npm run build` in `platform_web/`: passed.
- `npm install`, `npm run typecheck`, `npm run test`, and `npm run validate:manifest` in `plugins/`: passed.
- Cross-root import checks: `rg "browser\.local/(run|platform_web|plugins)" platform` and `rg "browser\.local/(platform|platform_web|plugins)" run` returned no matches.
- `scripts/check-all.sh`: passed.
- `scripts/check-structure.sh`: passed.
- Browser walkthrough: Vite dev server at `http://127.0.0.1:5173/`; desktop 1440x900 and mobile 390x844 checks confirmed required labels, 5 navigation items, 3 metric cards, no nav/metric/header overlap, and mobile document width equal to viewport.
- `openspec validate establish-development-runtime-baseline --strict`: passed.

## Implementation Handoff

```text
Implement OpenSpec change: establish-development-runtime-baseline

Scope:
- Implement only openspec/changes/establish-development-runtime-baseline/.
- Add runtime/tooling baselines for platform, run, platform_web, and plugins.
- Do not implement platform business APIs, run job execution, log ingest, artifact transfer, plugin marketplace workflows, billing, cloud host sales, or agent-provider/cloud-provider workflows.

Read first:
- AGENTS.md
- platform/AGENTS.md
- run/AGENTS.md
- platform_web/AGENTS.md
- plugins/AGENTS.md
- openspec/changes/bootstrap-game-server-platform-architecture/proposal.md
- openspec/changes/bootstrap-game-server-platform-architecture/design.md
- openspec/changes/architecture-delivery-stream/delivery-plan.md
- openspec/changes/establish-development-runtime-baseline/proposal.md
- openspec/changes/establish-development-runtime-baseline/design.md
- openspec/changes/establish-development-runtime-baseline/tasks.md

Required closure:
- Mark task checkboxes complete only after evidence exists.
- Run platform Go tests, run Go tests, platform_web install/typecheck/test/build, plugin install/typecheck/test/schema validation, the root full-check script, scripts/check-structure.sh, and openspec validate establish-development-runtime-baseline --strict.
- Because platform_web pages are touched, start the dev server and perform a browser walkthrough at desktop and mobile widths before claiming the UI is accepted.
- Stop after this change is closed; do not start implement-platform-core-domain in the same chat unless explicitly asked.
```