#127 feat: repository wrapper invoking the generated hooks

[RAprogramm]

Closes #127

The orphan rule keeps a user crate from implementing {Entity}Hooks for sqlx::PgPool — both the trait and the type are foreign there — so the repository impl on the pool could never call hooks, and the documented answer was to call them by hand at the service layer.

#[entity(hooks)] now also emits {Entity}Repo<H>, the type that owns both:

let repo = UserRepo::new(pool, Audit);

let user = repo.create(dto).await?;      // before_create → INSERT → after_create
let found = repo.find_by_id(id).await?;  // reads carry no hooks

Operation	Hooks
create, save	before_create may rewrite the DTO, after_create sees the persisted row
update	before_update may rewrite the patch
delete	after_delete only when a row was actually affected
hard_delete, restore	on soft-delete entities
everything else	reaches the pool through Deref, unchanged

A failing before_* aborts before anything is written. The hook error only has to convert into the repository error, so hooks keep their own error type — this is the RFC's option A, with the delegation done through Deref so the wrapper answers every repository method instead of re-declaring them.

Backward compatible: the bare pool path is untouched, and manual wiring keeps working.

Four live-Postgres cases cover the order of calls across create, update, delete and restore; that a refusing before_create leaves the table empty and never runs the after hook; that a refusing before_delete leaves the row in place; and that a read invokes nothing. examples/hooks is rewritten around the wrapper — the handlers no longer call hooks by hand. README, the module docs and the hooks page in all five wiki languages are updated.

[codecov]

Codecov Report

❌ Patch coverage is 90.00000% with 7 lines in your changes missing coverage. Please review.
✅ All tests successful. No failed tests found.

Files with missing lines	Patch %	Lines
...tes/entity-derive-impl/src/entity/hooks/wrapper.rs	89.85%	7 Missing ⚠️

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