chore: bootstrap repo scaffolding (M0.1)

Adds the §1.2 scaffolding required by IMPLEMENTATION_PLAN.md M0.1:
README, CONTRIBUTING, CODEOWNERS, CHANGELOG, PR + issue templates,
CI workflow, release workflow, LICENSE, commitlint, cliff config,
.editorconfig, .gitignore, .env.example.

Refs: M0.1

README.md

@@ -1,3 +1,59 @@
 # portal
 
-Next.js 15 customer area + backstage.
+Next.js 15 customer area + backstage.
+
+> Part of the **Breakpilot Platform**. For the big picture see [`platform/docs`](https://gitea.meghsakha.com/platform/docs):
+> [Architecture](https://gitea.meghsakha.com/platform/docs/src/branch/main/PLATFORM_ARCHITECTURE.md) ·
+> [Infrastructure](https://gitea.meghsakha.com/platform/docs/src/branch/main/INFRASTRUCTURE.md) ·
+> [Product Integration Spec](https://gitea.meghsakha.com/platform/docs/src/branch/main/PRODUCT_INTEGRATION_SPEC.md) ·
+> [Implementation Plan](https://gitea.meghsakha.com/platform/docs/src/branch/main/IMPLEMENTATION_PLAN.md)
+
+## What this is
+
+Next.js 15 customer area + backstage. Scaffolded under milestone M5.1. See [`platform/docs`](https://gitea.meghsakha.com/platform/docs) for the full architecture context.
+
+**Plane:** Control
+**Owner:** @sharang
+**Status:** pre-alpha
+**Linked milestone:** [M5.1](https://gitea.meghsakha.com/platform/docs/src/branch/main/IMPLEMENTATION_PLAN.md)
+
+## Run locally
+
+```bash
+# prerequisites: see CONTRIBUTING.md for tooling once code lands
+make dev          # starts dependencies + this service on http://localhost:3000
+make test         # unit + integration
+make e2e          # only if this repo ships user-facing flows
+```
+
+Local secrets come from `.env.local` (gitignored). Template at `.env.example`.
+
+## Endpoints / surface
+
+{{For services: list the top-level routes or commands.
+For libraries: list the public API entry points.
+For IaC: list the make targets.}}
+
+## Deployment
+
+| Env   | URL                                  | How                                  |
+|---|---|---|
+| dev   | `http://localhost:3000`          | `make dev`                           |
+| stage | `https://portal.stage.yourplatform.com` | auto on merge to `main`         |
+| prod  | `https://portal.yourplatform.com`  | manual: tag `vX.Y.Z` + sign-off      |
+
+Rollback: `orca rollout undo portal --env={{env}}`.
+
+## Observability
+
+- Traces, logs, metrics: [SigNoz](https://signoz.meghsakha.com) — service name `portal`
+- Audit events: Tenant Registry `/audit` (Retraced-shape schema)
+- On-call: `oncall@yourplatform.com` · runbook at `platform/docs/runbooks/portal.md`
+
+## Contributing
+
+See [`CONTRIBUTING.md`](./CONTRIBUTING.md). TL;DR: branch from main, open a PR, 1 review + green CI, squash-merge.
+
+## License
+
+MIT — see [`LICENSE`](./LICENSE).