feat(agents): wire agent_definitions and opencode.json agents into precedence chain

- Modified agent-config-handler.ts to load and integrate both new agent sources
- Added loadAgentDefinitions() and readOpencodeConfigAgents() calls in loading phase
- Integrated both sources into agent precedence chains (both Sisyphus-enabled and disabled paths)
- Added detailed logging for new agent sources
- Added filtering logic to respect disabled_agents configuration
- Extended agent-config-handler.test.ts with 7 new integration tests
- All tests passing (18/18 integration, 65/65 loader suite)

Wave 3 of agent definitions enhancement complete.

src/plugin-handlers/agent-config-handler.ts

@@ -14,7 +14,14 @@ import {
   discoverProjectClaudeSkills,
   discoverUserClaudeSkills,
 } from "../features/opencode-skill-loader";
-import { loadProjectAgents, loadUserAgents, loadOpencodeGlobalAgents, loadOpencodeProjectAgents } from "../features/claude-code-agent-loader";
+import { 
+  loadProjectAgents, 
+  loadUserAgents, 
+  loadOpencodeGlobalAgents, 
+  loadOpencodeProjectAgents,
+  loadAgentDefinitions,
+  readOpencodeConfigAgents,
+} from "../features/claude-code-agent-loader";
 import type { PluginComponents } from "./plugin-components-loader";
 import { reorderAgentsByPriority } from "./agent-priority-order";
 import { remapAgentKeysToDisplayNames } from "./agent-key-remapper";
@@ -33,7 +40,6 @@ type AgentConfigRecord = Record<string, Record<string, unknown> | undefined> & {
 function getConfiguredDefaultAgent(config: Record<string, unknown>): string | undefined {
   const defaultAgent = config.default_agent;
   if (typeof defaultAgent !== "string") return undefined;
-
   const trimmedDefaultAgent = defaultAgent.trim();
   return trimmedDefaultAgent.length > 0 ? trimmedDefaultAgent : undefined;
 }
@@ -100,6 +106,11 @@ export async function applyAgentConfig(params: {
   const opencodeProjectAgents = loadOpencodeProjectAgents(params.ctx.directory);
   const rawPluginAgents = params.pluginComponents.agents;
 
+  const agentDefinitionAgents = params.pluginConfig.agent_definitions
+    ? loadAgentDefinitions(params.pluginConfig.agent_definitions, "definition-file")
+    : {};
+  const opencodeConfigAgents = readOpencodeConfigAgents(params.ctx.directory);
+
   const pluginAgents = Object.fromEntries(
     Object.entries(rawPluginAgents).map(([key, value]) => {
       if (!value) return [key, value];
@@ -118,6 +129,8 @@ export async function applyAgentConfig(params: {
     ...Object.entries(opencodeGlobalAgents),
     ...Object.entries(opencodeProjectAgents),
     ...Object.entries(pluginAgents).filter(([, config]) => config !== undefined),
+    ...Object.entries(agentDefinitionAgents),
+    ...Object.entries(opencodeConfigAgents),
   ]
     .filter(([, config]) => config != null)
     .map(([name, config]) => ({
@@ -127,6 +140,20 @@ export async function applyAgentConfig(params: {
         : "",
     }));
 
+  log(
+    "[agent-config-handler] Agent sources loaded",
+    {
+      user: Object.keys(userAgents).length,
+      project: Object.keys(projectAgents).length,
+      opencodeGlobal: Object.keys(opencodeGlobalAgents).length,
+      opencodeProject: Object.keys(opencodeProjectAgents).length,
+      plugin: Object.keys(pluginAgents).length,
+      agentDefinitions: Object.keys(agentDefinitionAgents).length,
+      opencodeConfig: Object.keys(opencodeConfigAgents).length,
+      config: Object.keys(configAgent ?? {}).length,
+    }
+  );
+
   const builtinAgents = await createBuiltinAgents(
     migratedDisabledAgents,
     params.pluginConfig.agents,
@@ -269,6 +296,14 @@ export async function applyAgentConfig(params: {
       opencodeProjectAgents,
       protectedBuiltinAgentNames,
     );
+    const filteredAgentDefinitionAgents = filterProtectedAgentOverrides(
+      agentDefinitionAgents,
+      protectedBuiltinAgentNames,
+    );
+    const filteredOpencodeConfigAgents = filterProtectedAgentOverrides(
+      opencodeConfigAgents,
+      protectedBuiltinAgentNames,
+    );
 
     params.config.agent = {
       ...agentConfig,
@@ -283,6 +318,8 @@ export async function applyAgentConfig(params: {
       ...filterDisabledAgents(filteredOpencodeGlobalAgents),
       ...filterDisabledAgents(filteredProjectAgents),
       ...filterDisabledAgents(filteredOpencodeProjectAgents),
+      ...filterDisabledAgents(filteredAgentDefinitionAgents),
+      ...filterDisabledAgents(filteredOpencodeConfigAgents),
       ...filteredConfigAgents,
       build: { ...migratedBuild, mode: "subagent", hidden: true },
       ...(planDemoteConfig ? { plan: planDemoteConfig } : {}),
@@ -311,6 +348,14 @@ export async function applyAgentConfig(params: {
       opencodeProjectAgents,
       protectedBuiltinAgentNames,
     );
+    const filteredAgentDefinitionAgents = filterProtectedAgentOverrides(
+      agentDefinitionAgents,
+      protectedBuiltinAgentNames,
+    );
+    const filteredOpencodeConfigAgents = filterProtectedAgentOverrides(
+      opencodeConfigAgents,
+      protectedBuiltinAgentNames,
+    );
 
     const defaultedConfigAgents = configAgent
       ? Object.fromEntries(
@@ -331,6 +376,8 @@ export async function applyAgentConfig(params: {
       ...filterDisabledAgents(filteredOpencodeGlobalAgents),
       ...filterDisabledAgents(filteredProjectAgents),
       ...filterDisabledAgents(filteredOpencodeProjectAgents),
+      ...filterDisabledAgents(filteredAgentDefinitionAgents),
+      ...filterDisabledAgents(filteredOpencodeConfigAgents),
       ...defaultedConfigAgents,
     };
   }