feat: add environment variables support for agents and collections

- Add envVars field to Agent and Collection models in Prisma schema
- Add envVars to UpdateAgentSchema and UpdateCollectionSchema types
- Implement env vars merging logic (agent overrides collection)
- Pass env vars through tool executor to sandbox
- Add UI for managing env vars in agent and collection settings pages
- Update API routes to handle envVars PATCH updates
- Refactor discord tool execute functions for biome compatibility

This allows users to configure tool-specific environment variables (like
DISCORD_BOT_TOKEN) at both the collection and agent level, with agent
settings taking precedence over collection settings.

packages/types/src/agent.ts

@@ -63,6 +63,8 @@ export const UpdateAgentSchema = z.object({
   // Executor configuration
   executorType: ExecutorTypeSchema.nullable().optional(),
   executorConfig: ExecutorConfigUpdateSchema,
+  // Tool environment variables
+  envVars: z.record(z.string(), z.string()).nullable().optional(),
 });
 
 export const AddCollectionToAgentSchema = z.object({

packages/types/src/collection.ts

@@ -44,6 +44,8 @@ export const UpdateCollectionSchema = z.object({
   // Executor configuration
   executorType: ExecutorTypeSchema.nullable().optional(),
   executorConfig: ExecutorConfigUpdateSchema,
+  // Tool environment variables
+  envVars: z.record(z.string(), z.string()).nullable().optional(),
 });
 
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