docs: record two-repo layout decision

.planning/PROJECT.md

@@ -103,6 +103,7 @@ Quality
 - **Compatibility**: `vue-fonoteka-app` and `fonoteka-mcp` must run unchanged; the Nuxt app's requests define the contract and response shapes are not improved during the port
 - **Realtime**: keep the Centrifugo server and port only the publisher and token issuing — the Nuxt client connects to Centrifugo directly
 - **Plugins**: compiled at build time; no runtime plugin loading without a decision note
+- **Two repositories**: `summercms.go` is the framework only (the `summer` packages, the CLI, the admin SPA shell, the parity harness tooling) and knows nothing about Płytarium; `fonoteka.go`, a sibling directory in the meta repo, is the application: a go.work workspace holding the ported plugins (user, websockets, translate, feedback, sitemap, fonoteka) and the app binary, requiring the framework by module path with a local replace during development. Roadmap phases name which repo each plan writes to; planning docs stay in `summercms.go/.planning`
 - **Workflow**: lean planning (few, large plans per phase), a plan-count checkpoint before PLAN.md files are written, unit tests as the last plan of every phase, `go vet` and `go test ./...` green at every commit
 - **Commits**: no co-author tags; one logical change per commit; planning docs and code in separate commits
 - **Core plugin contracts**: the PHP user, blog, pages and payment plugins are shared across many projects; the Go ports must preserve their contracts and the PHP originals are not changed as part of this project
@@ -127,6 +128,7 @@ Quality
 | swaggo/swag for OpenAPI, not Huma | Comment annotations on plain net/http handlers keep 154 ported routes byte-compatible; Huma would reshape every handler | — Pending |
 | GORM + River share one `*sql.DB` (pgx stdlib) with a separate pgx pool for LISTEN/NOTIFY | River's documented GORM integration; transactional enqueue inside GORM transactions | — Pending |
 | Parity harness is a day-one workstream | Fixture recording needs only the running PHP backend; it is the acceptance mechanism for every port phase | — Pending |
+| Framework and application in two repos from day one (`summercms.go`, `fonoteka.go`) | Retrofitting the split later is more disruptive; shared stack plugins can be extracted for keios.eu without touching the framework; the framework never imports an app | — Pending (chosen 2026-09-16) |
 
 ## Evolution
 
@@ -146,4 +148,4 @@ This document evolves at phase transitions and milestone boundaries.
 4. Update Context with current state
 
 ---
-*Last updated: 2026-09-16 after project research*
+*Last updated: 2026-09-16 after requirements definition*