chore(cleanup): remove dead Module stubs and unused imports; restore deferred files

Deletes 21 Module.kt scaffolding objects that were never wired into any DI
registry. Removes unused imports across 8 production and 3 test files.

Restores StageExecutor, CyclePolicyResolver, PolicyValidation, and
ReplayContractTest — these are deferred features, not dead code.

plugins/compressors/src/main/kotlin/com/correx/plugins/compressors/Module.kt

@@ -1,3 +0,0 @@
-package com.correx.plugins.compressors
-
-object Module

plugins/policies/src/main/kotlin/com/correx/plugins/policies/Module.kt

@@ -1,3 +0,0 @@
-package com.correx.plugins.policies
-
-object Module

plugins/providers/src/main/kotlin/com/correx/plugins/providers/Module.kt

@@ -1,3 +0,0 @@
-package com.correx.plugins.providers
-
-object Module

plugins/stages/src/main/kotlin/com/correx/plugins/stages/Module.kt

@@ -1,3 +0,0 @@
-package com.correx.plugins.stages
-
-object Module

plugins/tools/src/main/kotlin/com/correx/plugins/tools/Module.kt

@@ -1,3 +0,0 @@
-package com.correx.plugins.tools
-
-object Module

plugins/transitions/src/main/kotlin/com/correx/plugins/transitions/Module.kt

@@ -1,3 +0,0 @@
-package com.correx.plugins.transitions
-
-object Module

plugins/validators/src/main/kotlin/com/correx/plugins/validators/Module.kt

@@ -1,3 +0,0 @@
-package com.correx.plugins.validators
-
-object Module