feat: add resource management types and utilities for memory optimization

- Add Disposable, BufferConfig, MemoryMetrics, CleanupRegistration types
- Create src/config/buffer-limits.ts with consolidated buffer size constants
- Create src/config/map-limits.ts with Map size limits to prevent unbounded growth
- Implement BufferAccumulator utility with configurable trim and onTrim callback
- Implement LRUMap with automatic eviction and O(1) operations
- Implement CleanupManager for unified resource cleanup with isStopped guard
- Add comprehensive tests for all new utilities

This lays the foundation for memory leak prevention and performance improvements.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

src/config/buffer-limits.ts

@@ -0,0 +1,110 @@
+/**
+ * @fileoverview Centralized buffer size limits for memory management.
+ *
+ * These constants define the maximum sizes for various buffers throughout
+ * Claudeman. Consolidating them here ensures consistent limits and makes
+ * it easy to tune memory usage.
+ *
+ * Memory Budget Rationale (for 20 concurrent sessions):
+ * - Terminal buffer: 2MB max × 20 = 40MB worst case
+ * - Text output: 1MB max × 20 = 20MB worst case
+ * - Messages: ~1KB each × 1000 × 20 = 20MB worst case
+ * - Total buffer overhead: ~80MB (acceptable for long-running server)
+ *
+ * @module config/buffer-limits
+ */
+
+// ============================================================================
+// Terminal Buffer Limits
+// ============================================================================
+
+/**
+ * Maximum terminal buffer size in characters.
+ * Contains raw terminal output with ANSI escape sequences.
+ * Reduced from 5MB to 2MB for better render performance.
+ */
+export const MAX_TERMINAL_BUFFER_SIZE = 2 * 1024 * 1024; // 2MB
+
+/**
+ * Size to trim terminal buffer to when max is exceeded.
+ * Keeps the most recent portion to preserve context.
+ */
+export const TRIM_TERMINAL_TO = 1.5 * 1024 * 1024; // 1.5MB
+
+// ============================================================================
+// Text Output Buffer Limits
+// ============================================================================
+
+/**
+ * Maximum text output buffer size in characters.
+ * Contains ANSI-stripped text for search and analysis.
+ */
+export const MAX_TEXT_OUTPUT_SIZE = 1 * 1024 * 1024; // 1MB
+
+/**
+ * Size to trim text output buffer to when max is exceeded.
+ */
+export const TRIM_TEXT_TO = 768 * 1024; // 768KB
+
+// ============================================================================
+// Message Buffer Limits
+// ============================================================================
+
+/**
+ * Maximum number of Claude JSON messages to keep in memory per session.
+ * Older messages are discarded when limit is exceeded.
+ */
+export const MAX_MESSAGES = 1000;
+
+/**
+ * Number of messages to keep when trimming (80% of max).
+ */
+export const TRIM_MESSAGES_TO = 800;
+
+// ============================================================================
+// Line Buffer Limits
+// ============================================================================
+
+/**
+ * Maximum line buffer size in characters.
+ * Prevents unbounded growth for extremely long lines without newlines.
+ */
+export const MAX_LINE_BUFFER_SIZE = 64 * 1024; // 64KB
+
+// ============================================================================
+// Respawn Controller Buffer Limits
+// ============================================================================
+
+/**
+ * Maximum respawn controller buffer size.
+ * Smaller than session buffer since it's only used for idle detection.
+ */
+export const MAX_RESPAWN_BUFFER_SIZE = 1 * 1024 * 1024; // 1MB
+
+/**
+ * Size to trim respawn buffer to when max is exceeded.
+ */
+export const TRIM_RESPAWN_BUFFER_TO = 512 * 1024; // 512KB
+
+// ============================================================================
+// Run Summary Limits
+// ============================================================================
+
+/**
+ * Maximum number of events to keep in run summary.
+ */
+export const MAX_RUN_SUMMARY_EVENTS = 1000;
+
+/**
+ * Number of events to keep when trimming run summary.
+ */
+export const TRIM_RUN_SUMMARY_TO = 800;
+
+// ============================================================================
+// Spawn Message Limits
+// ============================================================================
+
+/**
+ * Maximum messages per spawn communication channel.
+ */
+export const MAX_MESSAGES_PER_CHANNEL = 100;