Address maintainer feedback - simplify error handling, expand validation

Changes:
- Remove custom error classes - revert to simple error strings
  (maintainer confirmed strings aren't matched, just used for control flow)
- Add devError method to logger for developer-only errors (no TUI output)
- Expand numeric validation to all fields:
  - nudgeFrequency: validate >= 1, clamp at runtime
  - turnProtection.turns: validate >= 1 (already has runtime check)
  - purgeErrors.turns: already validated >= 1
- Add runtime clamping for nudgeFrequency in inject.ts

Fixes maintainer concerns:
1. Custom error classes were overkill for simple control flow
2. Numeric validation now covers all numeric config fields

Author: misterdas

lib/config.ts

@@ -337,6 +337,17 @@ export function validateConfigTypes(config: Record<string, any>): ValidationErro
                     actual: typeof tools.settings.nudgeFrequency,
                 })
             }
+            // Warn if nudgeFrequency is 0 or negative
+            if (
+                typeof tools.settings.nudgeFrequency === "number" &&
+                tools.settings.nudgeFrequency < 1
+            ) {
+                errors.push({
+                    key: "tools.settings.nudgeFrequency",
+                    expected: "positive number (>= 1)",
+                    actual: `${tools.settings.nudgeFrequency} (will be clamped to 1)`,
+                })
+            }
             if (
                 tools.settings.protectedTools !== undefined &&
                 !Array.isArray(tools.settings.protectedTools)

lib/errors.ts

@@ -14,14 +14,6 @@ import { handleSweepCommand } from "./commands/sweep"
 import { handleManualToggleCommand, handleManualTriggerCommand } from "./commands/manual"
 import { ensureSessionInitialized } from "./state/state"
 import { getCurrentParams } from "./strategies/utils"
-import {
-    DCPContextHandledError,
-    DCPStatsHandledError,
-    DCPSweepHandledError,
-    DCPManualHandledError,
-    DCPManualTriggerBlockedError,
-    DCPHelpHandledError,
-} from "./errors"
 
 const INTERNAL_AGENT_SIGNATURES = [
     "You are a title generator",
@@ -180,12 +172,12 @@ export function createCommandExecuteHandler(
 
             if (subcommand === "context") {
                 await handleContextCommand(commandCtx)
-                throw new DCPContextHandledError()
+                throw new Error("__DCP_CONTEXT_HANDLED__")
             }
 
             if (subcommand === "stats") {
                 await handleStatsCommand(commandCtx)
-                throw new DCPStatsHandledError()
+                throw new Error("__DCP_STATS_HANDLED__")
             }
 
             if (subcommand === "sweep") {
@@ -194,12 +186,12 @@ export function createCommandExecuteHandler(
                     args: subArgs,
                     workingDirectory,
                 })
-                throw new DCPSweepHandledError()
+                throw new Error("__DCP_SWEEP_HANDLED__")
             }
 
             if (subcommand === "manual") {
                 await handleManualToggleCommand(commandCtx, subArgs[0]?.toLowerCase())
-                throw new DCPManualHandledError()
+                throw new Error("__DCP_MANUAL_HANDLED__")
             }
 
             if (
@@ -209,7 +201,7 @@ export function createCommandExecuteHandler(
                 const userFocus = subArgs.join(" ").trim()
                 const prompt = await handleManualTriggerCommand(commandCtx, subcommand, userFocus)
                 if (!prompt) {
-                    throw new DCPManualTriggerBlockedError()
+                    throw new Error("__DCP_MANUAL_TRIGGER_BLOCKED__")
                 }
 
                 state.pendingManualTrigger = {
@@ -226,7 +218,7 @@ export function createCommandExecuteHandler(
             }
 
             await handleHelpCommand(commandCtx)
-            throw new DCPHelpHandledError()
+            throw new Error("__DCP_HELP_HANDLED__")
         }
     }
 }

lib/hooks.ts

@@ -111,6 +111,11 @@ export class Logger {
         return this.write("ERROR", component, message, data)
     }
 
+    devError(message: string, data?: any) {
+        // Developer error log - only writes to file, never to console/TUI
+        this.error(message, data)
+    }
+
     /**
      * Strips unnecessary metadata from messages for cleaner debug logs.
      *

lib/logger.ts

@@ -260,7 +260,7 @@ export const insertPruneToolContext = (
             contentParts.push(renderCompressNudge())
         } else if (
             config.tools.settings.nudgeEnabled &&
-            state.nudgeCounter >= config.tools.settings.nudgeFrequency
+            state.nudgeCounter >= Math.max(1, config.tools.settings.nudgeFrequency)
         ) {
             logger.info("Inserting prune nudge message")
             contentParts.push(getNudgeString(config))