chore: add github copilot code review instructions (#43901)

## Summary

Adds `.github/copilot-instructions.md` to configure GitHub Copilot Code
Review with telemetry and testing guidelines. Replaces CodeRabbit as our
automated PR reviewer. Copilot will now advisory-comment when PRs touch
growth-oriented components (onboarding, upgrade CTAs, A/B experiments)
without telemetry tracking, or when Studio changes lack appropriate test
coverage.

## Changes

- Add `.github/copilot-instructions.md` with:
- Telemetry review rules: event naming (`[object]_[verb]`), property
conventions, `useTrack` enforcement, missing tracking suggestions for
growth surfaces
- Testing review rules: logic extraction to `.utils.ts`, test type
decision tree, file naming conventions
  - Repo context and references to full Claude skill docs

## Testing

- [x] Verified `.github/copilot-instructions.md` is the correct path for
Copilot Code Review
- [x] Rules are condensed from existing Claude skills
(`telemetry-standards`, `studio-testing`) — verified alignment

## Linear

- fixes GROWTH-698

---------

Co-authored-by: Copilot Autofix powered by AI <175728472+Copilot@users.noreply.github.com>

.github/copilot-instructions.md

@@ -0,0 +1,100 @@
+# Copilot Code Review Instructions
+
+## Repo Context
+
+This is a TypeScript/Next.js/React monorepo:
+
+- `apps/studio/` — Supabase Dashboard (primary review target)
+- `apps/www/` — Marketing site
+- `apps/docs/` — Documentation
+- `packages/common/` — Shared code including telemetry definitions
+
+---
+
+## Telemetry Review Rules
+
+These rules apply to changes in `apps/studio/` and `packages/common/telemetry-constants.ts`. All comments are **advisory** — suggest, do not request changes.
+
+### When to Review for Telemetry
+
+1. **Changes to `packages/common/telemetry-constants.ts`** — validate event naming, property conventions, and JSDoc accuracy.
+2. **Growth-oriented components adding user interactions without tracking** — suggest adding telemetry when a PR adds buttons, forms, toggles, or modals in components that affect user acquisition, activation, or conversion:
+   - Onboarding / getting started flows
+   - Connect / setup wizards
+   - Upgrade / billing CTAs and modals
+   - A/B experiment variants (anything using `usePHFlag`)
+
+When tracking is missing, comment: _"This adds a user interaction that may benefit from tracking."_ Then propose an event name and `useTrack()` call.
+
+### Event Naming
+
+Format: `[object]_[verb]` in snake_case.
+
+Prefer verbs that already exist in `packages/common/telemetry-constants.ts` (reuse existing patterns wherever possible). Common examples include: `opened`, `clicked`, `submitted`, `created`, `removed`, `updated`, `retrieved`, `intended`, `evaluated`, `added`, `enabled`, `disabled`, `copied`, `exposed`, `failed`, `converted`, `closed`, `completed`, `applied`, `sent`.
+
+Flag these:
+- Inconsistent or overly generic verbs that don't match existing patterns (e.g. `saved`, `viewed`, `seen`, `pressed`)
+- Wrong order: `click_product_card` → should be `product_card_clicked`
+- Wrong casing: `productCardClicked` → should be `product_card_clicked`
+- Passive view tracking on page load (`dashboard_viewed`, `page_loaded`) — exception: `_exposed` events for A/B experiments are valid
+
+### Event Properties
+
+- **camelCase** for new events; match existing convention when extending an event
+- Names must be self-explanatory — flag generic names like `label`, `value`, `name`, `data`
+- Check `packages/common/telemetry-constants.ts` for similar events and verify property names are consistent (e.g., don't use `aiType` if related events use `assistantType`)
+- Never track PII (emails, names, IPs)
+
+### Event Implementation
+
+- Import `useTrack` from `lib/telemetry/track` — prefer `useTrack` for new telemetry and avoid introducing new `useSendEventMutation` usage
+- New events must have a TypeScript interface in `packages/common/telemetry-constants.ts`:
+  - Include `@group Events` and `@source` JSDoc tags; add `@page` when applicable (for page-specific events)
+  - Add the interface to the `TelemetryEvent` union type
+- Flag `@source` descriptions that don't match the actual implementation; when `@page` is present, validate that it matches the actual page usage
+
+### Correct Pattern
+
+```typescript
+import { useTrack } from 'lib/telemetry/track'
+
+const track = useTrack()
+track('product_card_clicked', {
+  productType: 'database',
+  planTier: 'pro',
+  source: 'dashboard',
+})
+```
+
+---
+
+## Testing Review Rules
+
+These rules apply to changes in `apps/studio/` that add or modify React components or utility functions. All comments are **advisory**.
+
+### Core Principle
+
+Push logic out of React components into pure `.utils.ts` functions, then test those functions exhaustively. Only use component tests for complex UI interactions.
+
+### When to Comment
+
+- PR adds **business logic inline in a component** that could be extracted to a `ComponentName.utils.ts` file next to the component and unit tested at `tests/components/.../ComponentName.utils.test.ts`
+- PR adds a **utility function without test coverage**
+- PR uses **component tests for pure logic** that should be a unit test on a pure function
+- PR adds a **feature used in both self-hosted and platform** without E2E test consideration
+
+### Which Test Type to Suggest
+
+- **Pure transformation** (parse, format, validate, compute) → extract to `.utils.ts` + unit test with vitest
+- **Complex UI interaction** → component test with `customRender` (or E2E if shared with self-hosted)
+- **E2E tests** should cover both click interactions AND keyboard shortcuts
+- **No tests at all** for non-trivial changes → nudge to add coverage
+
+---
+
+## References
+
+For the full, authoritative versions of these standards:
+
+- Telemetry: `.claude/skills/telemetry-standards/SKILL.md`
+- Testing: `.claude/skills/studio-testing/SKILL.md`