docs(instructions): upgrade to Claude Code-optimized agent instructions

Rewrite copilot-instructions.md for agentic use: expand the models
design decision rationale, clarify integration-test architecture,
add release tag format with valid coach names, tighten Agent Mode
buckets with specific file references, add commit/branch review gate,
and add the no-cross-project-justification guideline.

Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: nanotaboada

.github/copilot-instructions.md

@@ -2,7 +2,9 @@
 
 ## Overview
 
-REST API for managing football players built with Python and FastAPI. Implements async CRUD operations with SQLAlchemy 2.0 (async), SQLite, Pydantic validation, and in-memory caching. Part of a cross-language comparison study (.NET, Go, Java, Rust, TypeScript).
+REST API for managing football players built with Python and FastAPI. Implements
+async CRUD operations with SQLAlchemy 2.0 (async), SQLite, Pydantic validation,
+and in-memory caching.
 
 ## Tech Stack
 
@@ -31,23 +33,49 @@ tools/          — standalone seed scripts (run manually, not via Alembic)
 tests/          — pytest integration tests
 ```
 
-**Layer rule**: `Routes → Services → SQLAlchemy → SQLite`. Routes handle HTTP concerns only; business logic belongs in services.
+**Layer rule**: `Routes → Services → SQLAlchemy → SQLite`. Routes handle HTTP
+concerns only; business logic belongs in services. Never skip a layer.
 
 ## Coding Guidelines
 
 - **Naming**: snake_case (files, functions, variables), PascalCase (classes)
 - **Type hints**: Required everywhere — functions, variables, return types
-- **Async**: All routes and service functions must be `async def`; use `AsyncSession` (never `Session`); use `aiosqlite` (never `sqlite3`); use SQLAlchemy 2.0 `select()` (never `session.query()`)
-- **API contract**: camelCase JSON via Pydantic `alias_generator=to_camel`; Python internals stay snake_case
-- **Models**: `PlayerRequestModel` (no `id`, used for POST/PUT) and `PlayerResponseModel` (includes `id: UUID`, used for GET/POST responses); never use the removed `PlayerModel`
-- **Primary key**: UUID surrogate key (`id`) — opaque, internal, used for GET by id only. UUID v4 for API-created records; UUID v5 (deterministic) for migration-seeded records. `squad_number` is the natural key — human-readable, domain-meaningful, used for all mutation endpoints (PUT, DELETE) and preferred for all external consumers
-- **Caching**: cache key `"players"` (hardcoded); clear on POST/PUT/DELETE; `X-Cache` header (HIT/MISS)
-- **Errors**: Catch specific exceptions with rollback in services; Pydantic validation returns 422 (not 400)
+- **Async**: All routes and service functions must be `async def`; use
+  `AsyncSession` (never `Session`); use `aiosqlite` (never `sqlite3`); use
+  SQLAlchemy 2.0 `select()` (never `session.query()`)
+- **API contract**: camelCase JSON via Pydantic `alias_generator=to_camel`;
+  Python internals stay snake_case
+- **Models**: `PlayerRequestModel` (no `id`, used for POST/PUT) and
+  `PlayerResponseModel` (includes `id: UUID`, used for GET/POST responses).
+  One request model intentionally covers both POST and PUT — per-operation
+  differences (conflict check on POST, mismatch guard on PUT) are handled at
+  the route layer, not by duplicating the model. Never reintroduce the removed
+  `PlayerModel`; it was removed because a single flat model conflated ORM,
+  request, and response concerns.
+- **Primary key**: UUID surrogate key (`id`) — opaque, internal, used for GET
+  by id only. UUID v4 for API-created records; UUID v5 (deterministic) for
+  migration-seeded records. `squad_number` is the natural key —
+  human-readable, domain-meaningful, used for all mutation endpoints (PUT,
+  DELETE) and preferred for all external consumers
+- **Caching**: cache key `"players"` (hardcoded); clear on POST/PUT/DELETE;
+  `X-Cache` header (HIT/MISS)
+- **Errors**: Catch specific exceptions with rollback in services; Pydantic
+  validation returns 422 (not 400); squad number mismatch on PUT returns 400
+  (not 422 — it is a semantic error, not a validation failure)
 - **Logging**: `logging` module only; never `print()`
 - **Line length**: 88; complexity ≤ 10
 - **Import order**: stdlib → third-party → local
-- **Tests**: naming pattern `test_request_{method}_{resource}_{context}_response_{outcome}`; docstrings single-line, concise; `tests/player_stub.py` for test data; `tests/test_main.py` excluded from Black
-- **Avoid**: sync DB access, mixing sync/async, `print()`, missing type hints, unhandled exceptions
+- **Tests**: integration tests against the real pre-seeded SQLite DB via
+  `TestClient` — no mocking. Naming pattern
+  `test_request_{method}_{resource}_{context}_response_{outcome}`;
+  docstrings single-line, concise; `tests/player_stub.py` for test data;
+  `tests/conftest.py` provides a `function`-scoped `client` fixture for
+  isolation; `tests/test_main.py` excluded from Black
+- **Decisions**: justify every decision on its own technical merits; never use
+  "another project does it this way" as a reason — that explains nothing and
+  may mean replicating a mistake
+- **Avoid**: sync DB access, mixing sync/async, `print()`, missing type hints,
+  unhandled exceptions
 
 ## Commands
 
@@ -77,11 +105,12 @@ docker compose down -v
 
 ### Pre-commit Checks
 
-1. Update `CHANGELOG.md` `[Unreleased]` section (Added / Changed / Fixed / Removed)
+1. Update `CHANGELOG.md` `[Unreleased]` section (Added / Changed / Fixed /
+   Removed)
 2. `uv run flake8 .` — must pass
 3. `uv run black --check .` — must pass
 4. `uv run pytest` — all tests must pass
-5. `uv run pytest --cov=./ --cov-report=term` — coverage must be >=80%
+5. `uv run pytest --cov=./ --cov-report=term` — coverage must be ≥80%
 6. Commit message follows Conventional Commits format (enforced by commitlint)
 
 ### Commits
@@ -90,45 +119,73 @@ Format: `type(scope): description (#issue)` — max 80 chars
 Types: `feat` `fix` `chore` `docs` `test` `refactor` `ci` `perf`
 Example: `feat(api): add player stats endpoint (#42)`
 
+### Releases
+
+Tags follow the format `v{MAJOR}.{MINOR}.{PATCH}-{COACH}` (e.g.
+`v2.0.0-capello`). The CD pipeline validates the coach name against a fixed
+list (A–Z):
+
+```
+ancelotti bielsa capello delbosque eriksson ferguson guardiola heynckes
+inzaghi klopp kovac low mourinho nagelsmann ottmar pochettino queiroz
+ranieri simeone tuchel unai vangaal wenger xavi yozhef zeman
+```
+
+Never suggest a release tag with a coach name not on this list.
+
 ## Agent Mode
 
 ### Proceed freely
 
-- Add/modify routes and endpoints
-- Service layer logic and cache management
-- Tests (maintain async patterns and naming convention)
+- Add/modify routes in `routes/player_route.py` and `routes/health_route.py`
+- Add/modify service methods in `services/player_service.py`
+- Add/modify Pydantic models in `models/player_model.py` (field additions or
+  docstring updates that don't change the API contract)
+- Tests in `tests/` — maintain async patterns, naming convention, and
+  integration-test approach (no mocking)
 - Documentation and docstring updates
 - Lint/format fixes
 - Refactoring within existing architectural patterns
 
 ### Ask before changing
 
-- Database schema (`schemas/player_schema.py` — no Alembic, use tools/ seed scripts manually)
+- Database schema (`schemas/player_schema.py` — no Alembic; changes require
+  manually updating `storage/players-sqlite3.db` and the seed scripts in
+  `tools/`)
+- `models/player_model.py` design decisions — especially splitting or merging
+  request/response models; discuss the rationale before restructuring
 - Dependencies (`pyproject.toml` with PEP 735 dependency groups)
 - CI/CD configuration (`.github/workflows/`)
-- Docker setup
-- API contracts (breaking Pydantic model changes)
-- Global error handling
+- Docker setup (`Dockerfile`, `docker-compose.yml`, `scripts/`)
+- Breaking API contract changes (field renames, type changes, removing fields)
+- Global error handling middleware
+- HTTP status codes assigned to existing error conditions
 
 ### Never modify
 
 - `.env` files (secrets)
+- `storage/players-sqlite3.db` directly — schema changes go through
+  `schemas/player_schema.py` and `tools/` seed scripts
 - Production configurations
-- Async/await patterns (mandatory throughout)
-- Type hints (mandatory throughout)
-- Core layered architecture
 
 ### Key workflows
 
-**Add an endpoint**: Add Pydantic model in `models/` → add async service method in `services/` with error handling → add route in `routes/` with `Depends(generate_async_session)` → add tests following naming pattern → run pre-commit checks.
+**Add an endpoint**: Add Pydantic model in `models/` if the request/response
+shape is new → add async service method in `services/` with error handling and
+rollback → add route in `routes/` with `Depends(generate_async_session)` →
+add tests following the naming pattern → run pre-commit checks.
 
-**Modify schema**: Update `schemas/player_schema.py` → manually update `storage/players-sqlite3.db` (preserve 26 players) → update `models/player_model.py` if API changes → update services and tests → run `pytest`.
+**Modify schema**: Update `schemas/player_schema.py` → manually update
+`storage/players-sqlite3.db` (preserve all 26 seeded players) → update
+`models/player_model.py` if the API shape changes → update services and tests
+→ run `pytest`.
 
-**After completing work**: Suggest a branch name (e.g. `feat/add-player-stats`) and a commit message following Conventional Commits including co-author line:
+**After completing work**: Propose a branch name and commit message for user
+approval. Do not create a branch, commit, or push until the user explicitly
+confirms. Commit message format:
 
 ```text
 feat(scope): description (#issue)
 
-Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>
-Co-authored-by: Claude <noreply@anthropic.com>
+Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>
 ```