fix(mod): move module path off the decommissioned gitea.d-ma.be host

go.mod declared this module under gitea.d-ma.be, the pre-rename host
(infra ADR-0004). That name still resolves in DNS but no longer serves --
HTTPS to it fails outright -- so the declared path pointed at nothing.

It built anyway, because a Go module does not have to be fetchable from its
own declared path to compile locally. That is exactly what made it durable
rot: nothing failed, so nothing flagged it. What it did break is anyone
trying to depend on this repo -- `go get git.d-ma.be/mathias/<repo>` fails on
the path mismatch, and an importer would have to spell the dead host.

Verified safe before changing: nothing in the estate requires this module
(checked every go.mod across the Go repos) -- these are leaf binaries, so the
rename breaks no importer.

Mechanical: module path plus every internal import rewritten, templ
regenerated where applicable. Verified after -- go build, go vet, go test and
golangci-lint (against a Go 1.26.1 toolchain, matching CI) all pass, and no
gitea.d-ma.be reference remains in any .go/.templ/.mod file.

Found by an estate-wide scan for the old host, prompted by the same rot
turning up in tapir internal/web/views.templ (tapir@4bafd5f).

internal/eval/eval_test.go

@@ -5,7 +5,7 @@ import (
 	"math/rand"
 	"testing"
 
-	"gitea.d-ma.be/mathias/jepa-fx-risk/internal/eval"
+	"git.d-ma.be/mathias/jepa-fx-risk/internal/eval"
 )
 
 func seededRNG(seed int64) *rand.Rand {