refactor: split internal/moltark into model, filefmt, module, engine

CLAUDE.md

@@ -19,7 +19,9 @@ go build ./cmd/moltark              # Go build (quick local check)
 bazelisk test //...                  # Full Bazel suite (CI-authoritative)
 go test ./...                        # Full Go suite
 go test -count=1 ./...               # Full suite (no cache)
-go test -count=1 ./internal/moltark/...   # Core package tests
+go test -count=1 ./internal/engine/...    # Engine tests (pipeline, resolve, plan, state)
+go test -count=1 ./internal/filefmt/...   # File format handler tests
+go test -count=1 ./internal/module/...    # Starlark module tests
 go test -count=1 ./tests/integration/...  # Integration tests only
 go test -count=1 ./tests/features/...     # Gherkin feature tests only
 
@@ -42,24 +44,19 @@ Use `-count=1` when changing snapshots or CLI behavior to avoid stale test-cache
 
 **CLI layer**: `cmd/moltark/main.go` -> `internal/cliapp/app.go` -> `internal/command/` (one file per subcommand: init, plan, apply, show, doctor, version). Uses `github.com/mitchellh/cli`.
 
-**Engine pipeline** (`internal/moltark/pipeline.go`): Five sequential phases:
-1. **Evaluate** - load `molt.star` via Starlark (`config.go`) into `DesiredModel` (projects + components)
-2. **Resolve** - resolve facts, providers, routed intents (`resolve.go`) into `ResolvedModel` with managed files
-3. **Inspect** - read current repo state: structured files (TOML/JSON/YAML), `.moltark/state.json`, `.gitattributes`
-4. **Persist** - build next state from desired+resolved model
-5. **Plan** - classify each owned path as create/update/no-op/drift/conflict (`plan.go`)
+**Package layout** (acyclic dependency order: model <- filefmt <- module <- engine):
 
-**Service** (`internal/moltark/service.go`): Orchestrates `Plan`, `Apply`, `Show`, `Doctor` operations. Apply re-runs the full pipeline and verifies intent hasn't changed before writing.
+- **`internal/model`** — Shared domain types and constants. All IR types (`DesiredModel`, `ResolvedModel`, `Plan`, `Change`, `State`, etc.), change status/reason enums, file format constants, module source identifiers, and clone helpers. Zero internal dependencies.
 
-**First-party modules** (`internal/moltark/module_*.go`): `moltark/core`, `moltark/python`, `astral/uv`. Go and Rust are target ecosystems but do not yet have first-party module depth.
+- **`internal/filefmt`** — Structured file format handlers. Path resolution for TOML (dot notation) and JSON/YAML (JSON Pointer), format-specific parsers/mutators (TOML, JSON, YAML), `.gitattributes` managed-block logic. Depends on model only.
 
-**Structured file mutation**: Format-specific mutators for TOML (`pyproject.go`), JSON (`jsonfile.go`), YAML (`yamlfile.go`) that write only owned paths.
+- **`internal/module`** — Starlark DSL and module system. Config loading (`LoadDesiredModel`, `InitRepository`), module registry, first-party modules (`moltark/core`, `moltark/python`, `astral/uv`), Starlark value conversion, and fact-ref value type. Depends on model + filefmt.
 
-**Types** (`internal/moltark/types.go`): All IR types -- `DesiredModel`, `ResolvedModel`, `Pipeline`, `Plan`, `Change`, `State`, etc.
+- **`internal/engine`** — Reconciliation engine. Five-phase pipeline (evaluate -> resolve -> inspect -> persist -> plan), service layer (`Plan`, `Apply`, `Show`, `Doctor`), change classification, state management, and plan rendering. Depends on model + filefmt + module.
 
 ## Testing Structure
 
-- **Package tests**: `internal/moltark/*_test.go` -- planner, resolver, mutator, state logic
+- **Package tests**: `internal/engine/*_test.go` (pipeline, resolve, plan, state), `internal/filefmt/*_test.go` (format handlers, paths), `internal/module/*_test.go` (config loading, core module)
 - **Integration snapshots**: `tests/integration/` -- copies fixture repos to temp dirs, runs CLI commands, snapshots output via `go-snaps`
 - **Gherkin features**: `tests/features/` -- behavioral scenarios via `godog`
 - **Fixtures**: `tests/fixtures/` -- real repository structures (molt.star + pyproject.toml + state.json)

internal/command/BUILD.bazel

@@ -13,5 +13,9 @@ go_library(
     ],
     importpath = "github.com/ophidiarium/moltark/internal/command",
     visibility = ["//:__subpackages__"],
-    deps = ["//internal/moltark"],
+    deps = [
+        "//internal/engine",
+        "//internal/model",
+        "//internal/module",
+    ],
 )

internal/command/apply.go

@@ -3,7 +3,7 @@ package command
 import (
 	"flag"
 
-	"github.com/ophidiarium/moltark/internal/moltark"
+	"github.com/ophidiarium/moltark/internal/engine"
 )
 
 type ApplyCommand struct {
@@ -26,7 +26,7 @@ func (c *ApplyCommand) Run(args []string) int {
 		return 1
 	}
 
-	c.printLine(moltark.RenderPlan(plan))
+	c.printLine(engine.RenderPlan(plan))
 	if plan.HasConflicts() {
 		c.errorf("Apply aborted due to conflicts.\n")
 		return 1
@@ -53,7 +53,7 @@ func (c *ApplyCommand) Run(args []string) int {
 	}
 
 	c.printLine("")
-	c.printLine(moltark.RenderApply(result))
+	c.printLine(engine.RenderApply(result))
 	return 0
 }
 

internal/command/doctor.go

@@ -3,7 +3,7 @@ package command
 import (
 	"flag"
 
-	"github.com/ophidiarium/moltark/internal/moltark"
+	"github.com/ophidiarium/moltark/internal/engine"
 )
 
 type DoctorCommand struct {
@@ -24,7 +24,7 @@ func (c *DoctorCommand) Run(args []string) int {
 		return 1
 	}
 
-	c.printLine(moltark.RenderDoctor(report))
+	c.printLine(engine.RenderDoctor(report))
 	if report.HasIssues {
 		return 1
 	}

internal/command/init.go

@@ -4,7 +4,8 @@ import (
 	"flag"
 	"fmt"
 
-	"github.com/ophidiarium/moltark/internal/moltark"
+	"github.com/ophidiarium/moltark/internal/model"
+	"github.com/ophidiarium/moltark/internal/module"
 )
 
 type InitCommand struct {
@@ -19,7 +20,7 @@ func (c *InitCommand) Run(args []string) int {
 		return 1
 	}
 
-	result, err := moltark.InitRepository(c.WorkingDir)
+	result, err := module.InitRepository(c.WorkingDir)
 	if err != nil {
 		c.errorf("Error: %s\n", err)
 		return 1
@@ -36,7 +37,7 @@ func (c *InitCommand) Help() string {
   %s when one does not already exist.
 
   This command does not reconcile pyproject.toml. Run "moltark plan"
-  and "moltark apply" after initialization.`, moltark.ProjectSpecFileName)
+  and "moltark apply" after initialization.`, model.ProjectSpecFileName)
 }
 
 func (c *InitCommand) Synopsis() string {

internal/command/meta.go

@@ -6,7 +6,7 @@ import (
 	"io"
 	"strings"
 
-	"github.com/ophidiarium/moltark/internal/moltark"
+	"github.com/ophidiarium/moltark/internal/engine"
 )
 
 type Meta struct {
@@ -16,8 +16,8 @@ type Meta struct {
 	Stderr     io.Writer
 }
 
-func (m Meta) service() moltark.Service {
-	return moltark.NewService()
+func (m Meta) service() engine.Service {
+	return engine.NewService()
 }
 
 func (m Meta) printf(format string, args ...any) {

internal/command/plan.go

@@ -4,7 +4,8 @@ import (
 	"flag"
 	"fmt"
 
-	"github.com/ophidiarium/moltark/internal/moltark"
+	"github.com/ophidiarium/moltark/internal/engine"
+	"github.com/ophidiarium/moltark/internal/model"
 )
 
 type PlanCommand struct {
@@ -26,7 +27,7 @@ func (c *PlanCommand) Run(args []string) int {
 		return 1
 	}
 
-	c.printLine(moltark.RenderPlan(plan))
+	c.printLine(engine.RenderPlan(plan))
 
 	if plan.HasConflicts() {
 		return 1
@@ -47,9 +48,9 @@ func (c *PlanCommand) Help() string {
 
 Options:
 
-  -detailed-exitcode    Return 2 when changes are planned.`, moltark.ProjectSpecFileName)
+  -detailed-exitcode    Return 2 when changes are planned.`, model.ProjectSpecFileName)
 }
 
 func (c *PlanCommand) Synopsis() string {
-	return fmt.Sprintf("Show repository changes required by %s", moltark.ProjectSpecFileName)
+	return fmt.Sprintf("Show repository changes required by %s", model.ProjectSpecFileName)
 }

internal/engine/BUILD.bazel

@@ -0,0 +1,40 @@
+load("@rules_go//go:def.bzl", "go_library", "go_test")
+
+go_library(
+    name = "engine",
+    srcs = [
+        "pipeline.go",
+        "plan.go",
+        "resolve.go",
+        "service.go",
+        "state.go",
+    ],
+    importpath = "github.com/ophidiarium/moltark/internal/engine",
+    visibility = ["//:__subpackages__"],
+    deps = [
+        "//internal/filefmt",
+        "//internal/model",
+        "//internal/module",
+    ],
+)
+
+go_test(
+    name = "engine_test",
+    size = "small",
+    srcs = [
+        "pipeline_test.go",
+        "plan_test.go",
+        "resolve_test.go",
+        "service_test.go",
+        "state_test.go",
+    ],
+    data = [
+        "//tests/fixtures:all_fixtures",
+    ],
+    embed = [":engine"],
+    deps = [
+        "//internal/filefmt",
+        "//internal/model",
+        "//internal/testrepo",
+    ],
+)