Stage 14: solver & dictionary split — consume published module + DAWG artifact (TODO-1/TODO-2)

- backend/go.mod pins gitea.iliadenisov.ru/developer/scrabble-solver v1.0.0; the engine's
  imports use the published module path; go.work drops the solver replace (GOPRIVATE fetches
  it directly from Gitea). The solver's wordlist/dictdawg are now public packages.
- CI (go-unit, integration): drop the solver sibling-clone, set GOPRIVATE, and download the
  dictionary DAWG release artifact (scrabble-dawg-<DICT_VERSION>.tar.gz from the new
  scrabble-dictionary repo) for BACKEND_DICT_DIR.
- Docs: ARCHITECTURE §5/§11/§13/§14 + backend/README updated to the published-module +
  release-artifact model. PLAN.md re-scoped Stage 14 to the split and added Stages 15 (deploy
  infra & test contour), 16 (prod contour), 17 (dual Telegram bots); TODO-1/TODO-2 marked done.

backend/internal/engine/bag.go

@@ -3,7 +3,7 @@ package engine
 import (
 	"math/rand"
 
-	"scrabble-solver/rules"
+	"gitea.iliadenisov.ru/developer/scrabble-solver/rules"
 )
 
 // blankTile marks a blank tile in a hand or in the bag, matching the

backend/internal/engine/bag_test.go

@@ -5,7 +5,7 @@ import (
 	"slices"
 	"testing"
 
-	"scrabble-solver/rules"
+	"gitea.iliadenisov.ru/developer/scrabble-solver/rules"
 )
 
 // allTiles returns the full multiset of tiles a bag is filled from, in ruleset

backend/internal/engine/decode.go

@@ -3,9 +3,9 @@ package engine
 import (
 	"fmt"
 
-	"scrabble-solver/board"
-	"scrabble-solver/rules"
-	"scrabble-solver/scrabble"
+	"gitea.iliadenisov.ru/developer/scrabble-solver/board"
+	"gitea.iliadenisov.ru/developer/scrabble-solver/rules"
+	"gitea.iliadenisov.ru/developer/scrabble-solver/scrabble"
 )
 
 // ActionKind classifies a turn in the move log.

backend/internal/engine/decode_test.go

@@ -3,7 +3,7 @@ package engine
 import (
 	"testing"
 
-	"scrabble-solver/scrabble"
+	"gitea.iliadenisov.ru/developer/scrabble-solver/scrabble"
 )
 
 // blankCellFlag is the bit board cells set for a blank tile (board.go encoding).

backend/internal/engine/domain.go

@@ -3,7 +3,7 @@ package engine
 import (
 	"fmt"
 
-	"scrabble-solver/scrabble"
+	"gitea.iliadenisov.ru/developer/scrabble-solver/scrabble"
 )
 
 // blankLetter is how a blank tile is written in the decoded, domain-facing API:

backend/internal/engine/engine.go

@@ -17,7 +17,7 @@ import (
 	"errors"
 	"fmt"
 
-	"scrabble-solver/rules"
+	"gitea.iliadenisov.ru/developer/scrabble-solver/rules"
 )
 
 // Variant identifies a Scrabble variant the backend offers. Each maps to a

backend/internal/engine/game.go

@@ -3,10 +3,10 @@ package engine
 import (
 	"fmt"
 
-	"scrabble-solver/board"
-	"scrabble-solver/rack"
-	"scrabble-solver/rules"
-	"scrabble-solver/scrabble"
+	"gitea.iliadenisov.ru/developer/scrabble-solver/board"
+	"gitea.iliadenisov.ru/developer/scrabble-solver/rack"
+	"gitea.iliadenisov.ru/developer/scrabble-solver/rules"
+	"gitea.iliadenisov.ru/developer/scrabble-solver/scrabble"
 )
 
 // scorelessLimit is the number of consecutive scoreless turns (passes and

backend/internal/engine/game_test.go

@@ -4,8 +4,8 @@ import (
 	"errors"
 	"testing"
 
-	"scrabble-solver/board"
-	"scrabble-solver/scrabble"
+	"gitea.iliadenisov.ru/developer/scrabble-solver/board"
+	"gitea.iliadenisov.ru/developer/scrabble-solver/scrabble"
 )
 
 // newEnglishGame starts a two-player English game with the given seed.

backend/internal/engine/helpers_test.go

@@ -7,8 +7,8 @@ import (
 	"runtime"
 	"testing"
 
-	"scrabble-solver/rules"
-	"scrabble-solver/scrabble"
+	"gitea.iliadenisov.ru/developer/scrabble-solver/rules"
+	"gitea.iliadenisov.ru/developer/scrabble-solver/scrabble"
 )
 
 // testVersion labels the single dictionary version the tests register.

backend/internal/engine/registry.go

@@ -9,7 +9,7 @@ import (
 
 	dawg "github.com/iliadenisov/dafsa"
 
-	"scrabble-solver/scrabble"
+	"gitea.iliadenisov.ru/developer/scrabble-solver/scrabble"
 )
 
 // dictFiles maps each variant to its committed DAWG filename, as built by

backend/internal/engine/registry_test.go

@@ -4,8 +4,8 @@ import (
 	"errors"
 	"testing"
 
-	"scrabble-solver/board"
-	"scrabble-solver/scrabble"
+	"gitea.iliadenisov.ru/developer/scrabble-solver/board"
+	"gitea.iliadenisov.ru/developer/scrabble-solver/scrabble"
 )
 
 // TestRegistryOpensEveryVariant checks that Open loads all three variants at the