docs: add module documentation in AsciiDoc with PlantUML diagrams

Generated by per-group subagents covering all 52 modules across:
core (18), infrastructure (10), apps (5), interfaces (3),
plugins (7), testing (9)

Documentation format:
- AsciiDoc (.adoc) files in docs/modules/<group>/
- PlantUML (.puml) files in docs/diagrams/
- .adoc files reference diagrams via include:: directives

Each doc covers: purpose, responsibilities, non-responsibilities,
key types, event flow, integration points, invariants, PlantUML
diagram, known issues, and open questions.

docs/modules/plugins/plugin-compressors.adoc

@@ -0,0 +1,48 @@
+= plugin-compressors
+
+== purpose
+
+No source files present. This directory is reserved for external compression plugins that implement custom context compression strategies beyond the built-in compressor. Currently a structural placeholder.
+
+== responsibilities
+
+* Declares the module structure for future compressor plugin definitions
+
+== non-responsibilities
+
+* This module has no source code, types, or runtime behavior
+
+== key types
+
+*No types defined.*
+
+== event flow
+
+None. Module has no source files.
+
+== integration points
+
+* No current dependencies or dependents
+
+== invariants
+
+* Not applicable — module is empty
+
+== PlantUML diagram
+
+[plantuml, plugin-compressors, "png"]
+----
+include::../../diagrams/plugin-compressors.puml[]
+----
+
+
+
+
+== known issues
+
+* This module contains no implementation — it is an empty placeholder
+
+== open questions
+
+* Will compressor plugins implement the `ContextCompressor` interface from `:core:context`?
+* What compression strategies (semantic chunking, summary, retrieval-based) are planned for plugins?

docs/modules/plugins/plugin-policies.adoc

@@ -0,0 +1,49 @@
+= plugin-policies
+
+== purpose
+
+No source files present. This directory is reserved for external policy plugins that define custom approval policies, gating rules, and compliance checks beyond the built-in approval engine. Currently a structural placeholder.
+
+== responsibilities
+
+* Declares the module structure for future policy plugin definitions
+
+== non-responsibilities
+
+* This module has no source code, types, or runtime behavior
+
+== key types
+
+*No types defined.*
+
+== event flow
+
+None. Module has no source files.
+
+== integration points
+
+* No current dependencies or dependents
+
+== invariants
+
+* Not applicable — module is empty
+
+== PlantUML diagram
+
+[plantuml, plugin-policies, "png"]
+----
+include::../../diagrams/plugin-policies.puml[]
+----
+
+
+
+
+== known issues
+
+* This module contains no implementation — it is an empty placeholder
+
+== open questions
+
+* Will policy plugins integrate with the `ApprovalEngine` interface from `:core:approvals`?
+* What policy types (role-based, time-based, compliance) are planned?
+* Will policies be evaluated before or after the approval engine's built-in checks?

docs/modules/plugins/plugin-providers.adoc

@@ -0,0 +1,49 @@
+= plugin-providers
+
+== purpose
+
+No source files present. This directory is reserved for external inference provider plugins that connect Correx to LLM backends beyond the built-in llama.cpp adapter. Currently a structural placeholder.
+
+== responsibilities
+
+* Declares the module structure for future inference provider plugin definitions
+
+== non-responsibilities
+
+* This module has no source code, types, or runtime behavior
+
+== key types
+
+*No types defined.*
+
+== event flow
+
+None. Module has no source files.
+
+== integration points
+
+* No current dependencies or dependents
+
+== invariants
+
+* Not applicable — module is empty
+
+== PlantUML diagram
+
+[plantuml, plugin-providers, "png"]
+----
+include::../../diagrams/plugin-providers.puml[]
+----
+
+
+
+
+== known issues
+
+* This module contains no implementation — it is an empty placeholder
+
+== open questions
+
+* Will provider plugins implement the `InferenceProvider` interface from `:core:inference`?
+* How will provider plugins register themselves with the `DefaultProviderRegistry`?
+* Will there be a provider marketplace or discovery mechanism?

docs/modules/plugins/plugin-stages.adoc

@@ -0,0 +1,48 @@
+= plugin-stages
+
+== purpose
+
+No source files present. This directory is reserved for external stage-type plugins that define custom stage execution behaviors beyond the built-in stage model. Currently a structural placeholder.
+
+== responsibilities
+
+* Declares the module structure for future stage plugin definitions
+
+== non-responsibilities
+
+* This module has no source code, types, or runtime behavior
+
+== key types
+
+*No types defined.*
+
+== event flow
+
+None. Module has no source files.
+
+== integration points
+
+* No current dependencies or dependents
+
+== invariants
+
+* Not applicable — module is empty
+
+== PlantUML diagram
+
+[plantuml, plugin-stages, "png"]
+----
+include::../../diagrams/plugin-stages.puml[]
+----
+
+
+
+
+== known issues
+
+* This module contains no implementation — it is an empty placeholder
+
+== open questions
+
+* Will stage plugins define custom execution strategies (parallel, branching, looping)?
+* How will stage plugins integrate with the `OrchestratorEngines` wiring?

docs/modules/plugins/plugin-tools.adoc

@@ -0,0 +1,48 @@
+= plugin-tools
+
+== purpose
+
+No source files present. This directory is reserved for external tool plugins that extend the Correx tool system beyond the built-in infrastructure tools (shell, file write, file edit). Currently a structural placeholder.
+
+== responsibilities
+
+* Declares the module structure for future tool plugin definitions
+
+== non-responsibilities
+
+* This module has no source code, types, or runtime behavior
+
+== key types
+
+*No types defined.*
+
+== event flow
+
+None. Module has no source files.
+
+== integration points
+
+* No current dependencies or dependents
+
+== invariants
+
+* Not applicable — module is empty
+
+== PlantUML diagram
+
+[plantuml, plugin-tools, "png"]
+----
+include::../../diagrams/plugin-tools.puml[]
+----
+
+
+
+
+== known issues
+
+* This module contains no implementation — it is an empty placeholder
+
+== open questions
+
+* Will tool plugins conform to a SPI interface, or be loaded via service loader configuration?
+* What isolation mechanism (subprocess, container, WASM) will external tool plugins use?

docs/modules/plugins/plugin-transitions.adoc

@@ -0,0 +1,48 @@
+= plugin-transitions
+
+== purpose
+
+No source files present. This directory is reserved for external transition evaluation plugins that implement custom transition conditions beyond the built-in evaluator. Currently a structural placeholder.
+
+== responsibilities
+
+* Declares the module structure for future transition plugin definitions
+
+== non-responsibilities
+
+* This module has no source code, types, or runtime behavior
+
+== key types
+
+*No types defined.*
+
+== event flow
+
+None. Module has no source files.
+
+== integration points
+
+* No current dependencies or dependents
+
+== invariants
+
+* Not applicable — module is empty
+
+== PlantUML diagram
+
+[plantuml, plugin-transitions, "png"]
+----
+include::../../diagrams/plugin-transitions.puml[]
+----
+
+
+
+
+== known issues
+
+* This module contains no implementation — it is an empty placeholder
+
+== open questions
+
+* Will transition plugins implement the `TransitionConditionEvaluator` functional interface?
+* What condition types (time-based, output-based, external signals) are planned?

docs/modules/plugins/plugin-validators.adoc

@@ -0,0 +1,48 @@
+= plugin-validators
+
+== purpose
+
+No source files present. This directory is reserved for external validation plugins that implement custom validation logic beyond the built-in validators (e.g., artifact payload validation). Currently a structural placeholder.
+
+== responsibilities
+
+* Declares the module structure for future validator plugin definitions
+
+== non-responsibilities
+
+* This module has no source code, types, or runtime behavior
+
+== key types
+
+*No types defined.*
+
+== event flow
+
+None. Module has no source files.
+
+== integration points
+
+* No current dependencies or dependents
+
+== invariants
+
+* Not applicable — module is empty
+
+== PlantUML diagram
+
+[plantuml, plugin-validators, "png"]
+----
+include::../../diagrams/plugin-validators.puml[]
+----
+
+
+
+
+== known issues
+
+* This module contains no implementation — it is an empty placeholder
+
+== open questions
+
+* Will validator plugins conform to the `Validator` functional interface from `:core:validation`?
+* Should validators be loaded at startup or discovered dynamically?