feat: config with agents rework

docs/guides/using-modules.md

@@ -32,7 +32,13 @@ modules/home-manager/
 │   └── zellij-ps.nix
 └── coding/         # Development tools
     ├── default.nix # Aggregates coding modules
-    └── editors.nix
+    ├── editors.nix
+    ├── opencode.nix # OpenCode non-agent config
+    └── agents/     # Per-tool agent deployment
+        ├── default.nix
+        ├── opencode.nix
+        ├── claude-code.nix
+        └── pi.nix
 ```
 
 ## Importing Modules
@@ -197,6 +203,61 @@ m3ta.coding.editors = {
 
 **Documentation**: [Editors Module](../modules/home-manager/coding/editors.md)
 
+### `coding.opencode`
+
+OpenCode AI coding assistant (non-agent config: theme, formatter, plugins).
+
+```nix
+coding.opencode = {
+  enable = true;
+  ohMyOpencodeSettings = {
+    agents.sisyphus.model = "anthropic/claude-opus-4-5";
+  };
+  extraSettings = {
+    provider.anthropic.name = "Anthropic";
+  };
+};
+```
+
+### `coding.agents.opencode`
+
+OpenCode agent deployment from canonical TOML definitions.
+
+```nix
+coding.agents.opencode = {
+  enable = true;
+  agentsInput = inputs.agents;
+  modelOverrides = {
+    chiron = "anthropic/claude-sonnet-4";
+  };
+  externalSkills = [
+    { src = inputs.skills-anthropic; }
+  ];
+};
+```
+
+### `coding.agents.claude-code`
+
+Claude Code agent deployment from canonical TOML definitions.
+
+```nix
+coding.agents.claude-code = {
+  enable = true;
+  agentsInput = inputs.agents;
+};
+```
+
+### `coding.agents.pi`
+
+Pi agent deployment from canonical TOML definitions.
+
+```nix
+coding.agents.pi = {
+  enable = true;
+  agentsInput = inputs.agents;
+};
+```
+
 ## Common Patterns
 
 ### Module Configuration