feat(agent): add system administration task patterns (fluent_cli-yi95)

Add SysadminPatternDetector with 11 built-in sysadmin patterns for
intelligent task reasoning:
- QEMU/KVM VM management
- VirtualBox VM management
- Disk image operations (qcow2, raw, conversion)
- Network configuration
- OS installation guidance
- Bootloader/GRUB configuration
- Package management (apt, dnf, pacman)
- Service/systemd management
- User and permission management
- System monitoring and performance
- Backup and recovery

Each pattern includes:
- Keyword detection for task matching
- Required tools list
- Step-by-step implementation guide
- Common pitfalls and warnings
- Safety notes for risky operations
- Example shell commands

Patterns are designed to help the agent handle terminal-bench tasks
like install-windows-xp that require VM setup and OS installation.

Includes 8 unit tests covering pattern detection and prompt generation.

Author: njfio

crates/fluent-agent/src/reasoning/mod.rs

@@ -9,12 +9,17 @@ pub mod chain_of_thought;
 pub mod enhanced_multi_modal;
 pub mod meta_reasoning;
 pub mod multi_modal;
+pub mod sysadmin_patterns;
 pub mod tree_of_thought;
 
 pub use algorithmic_patterns::{
     AlgorithmCategory, AlgorithmGuidance, AlgorithmPattern, AlgorithmPatternDetector,
     PatternDetectionResult,
 };
+pub use sysadmin_patterns::{
+    SysadminCategory, SysadminDetectionResult, SysadminGuidance, SysadminPattern,
+    SysadminPatternDetector,
+};
 pub use chain_of_thought::{ChainOfThoughtEngine, CoTConfig, CoTReasoningResult};
 pub use enhanced_multi_modal::{
     EnhancedMultiModalEngine, EnhancedReasoningConfig, EnhancedReasoningResult,
@@ -67,6 +72,7 @@ pub enum ReasoningCapability {
     AnalogicalReasoning,
     CausalReasoning,
     AlgorithmicReasoning,
+    SysadminReasoning,
 }
 
 /// Structured output from a reasoning step with validated schema