feat: complete DDD Phase 2 - add domain services, infrastructure layers, and shared components

- domain/value_objects: Add Topic, UserTitle, GoldenQuote, Statistics value objects
- domain/services: Add StatisticsCalculator, ReportGenerator domain services
- domain/exceptions: Add comprehensive domain exception hierarchy
- infrastructure/persistence: Add HistoryRepository for data storage
- infrastructure/llm: Add LLMClient wrapper for AstrBot providers
- infrastructure/config: Add ConfigManager for centralized configuration
- infrastructure/resilience: Add CircuitBreaker, RateLimiter, retry utilities
- application: Add SchedulingService, ReportingService application services
- shared: Add constants and TraceContext for request tracing

All imports verified in Docker container.

src/shared/__init__.py

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+"""
+Shared Module - Common utilities and constants
+"""
+
+from .constants import *
+from .trace_context import TraceContext
+
+__all__ = [
+    "TraceContext",
+    # Constants are exported via *
+]

src/shared/constants.py

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+"""
+Constants - Shared constants used across the plugin
+"""
+
+# Plugin metadata
+PLUGIN_NAME = "astrbot_plugin_qq_group_daily_analysis"
+PLUGIN_VERSION = "2.0.0"
+
+# Platform identifiers
+PLATFORM_ONEBOT = "onebot"
+PLATFORM_TELEGRAM = "telegram"
+PLATFORM_DISCORD = "discord"
+PLATFORM_SLACK = "slack"
+PLATFORM_LARK = "lark"
+
+SUPPORTED_PLATFORMS = [
+    PLATFORM_ONEBOT,
+    # Future platforms
+    # PLATFORM_TELEGRAM,
+    # PLATFORM_DISCORD,
+    # PLATFORM_SLACK,
+    # PLATFORM_LARK,
+]
+
+# Analysis defaults
+DEFAULT_MAX_TOPICS = 5
+DEFAULT_MAX_USER_TITLES = 10
+DEFAULT_MAX_GOLDEN_QUOTES = 5
+DEFAULT_MIN_MESSAGES = 50
+DEFAULT_MAX_TOKENS = 2000
+
+# Time periods
+HOUR_RANGES = {
+    "morning": (6, 12),
+    "afternoon": (12, 18),
+    "evening": (18, 24),
+    "night": (0, 6),
+}
+
+# Report formats
+REPORT_FORMAT_TEXT = "text"
+REPORT_FORMAT_MARKDOWN = "markdown"
+REPORT_FORMAT_IMAGE = "image"
+REPORT_FORMAT_HTML = "html"
+
+# Message content types
+CONTENT_TYPE_TEXT = "text"
+CONTENT_TYPE_IMAGE = "image"
+CONTENT_TYPE_EMOJI = "emoji"
+CONTENT_TYPE_STICKER = "sticker"
+CONTENT_TYPE_FILE = "file"
+CONTENT_TYPE_AUDIO = "audio"
+CONTENT_TYPE_VIDEO = "video"
+CONTENT_TYPE_REPLY = "reply"
+CONTENT_TYPE_AT = "at"
+CONTENT_TYPE_UNKNOWN = "unknown"
+
+# Analysis task states
+TASK_STATE_PENDING = "pending"
+TASK_STATE_RUNNING = "running"
+TASK_STATE_COMPLETED = "completed"
+TASK_STATE_FAILED = "failed"
+TASK_STATE_CANCELLED = "cancelled"
+
+# Error codes
+ERROR_INSUFFICIENT_DATA = "INSUFFICIENT_DATA"
+ERROR_LLM_FAILED = "LLM_FAILED"
+ERROR_PLATFORM_ERROR = "PLATFORM_ERROR"
+ERROR_CONFIG_ERROR = "CONFIG_ERROR"
+ERROR_TIMEOUT = "TIMEOUT"
+
+# Cache TTL (in seconds)
+CACHE_TTL_SHORT = 60  # 1 minute
+CACHE_TTL_MEDIUM = 300  # 5 minutes
+CACHE_TTL_LONG = 3600  # 1 hour
+CACHE_TTL_DAY = 86400  # 24 hours
+
+# Rate limiting defaults
+RATE_LIMIT_LLM_CALLS = 10  # calls per minute
+RATE_LIMIT_API_CALLS = 60  # calls per minute
+RATE_LIMIT_BURST = 5  # burst size
+
+# Retry defaults
+RETRY_MAX_ATTEMPTS = 3
+RETRY_BASE_DELAY = 1.0
+RETRY_MAX_DELAY = 30.0
+
+# File paths
+HISTORY_DIR = "history"
+CACHE_DIR = "cache"
+TEMP_DIR = "temp"

src/shared/trace_context.py

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+"""
+Trace Context - Request tracing and correlation
+
+Provides context for tracking requests across the plugin.
+"""
+
+import uuid
+from contextvars import ContextVar
+from dataclasses import dataclass, field
+from datetime import datetime
+from typing import Any, Dict, Optional
+
+# Context variable for current trace
+_current_trace: ContextVar[Optional["TraceContext"]] = ContextVar(
+    "current_trace", default=None
+)
+
+
+@dataclass
+class TraceContext:
+    """
+    Context for tracing requests through the plugin.
+
+    Provides correlation IDs and timing information for debugging
+    and monitoring.
+    """
+
+    trace_id: str = field(default_factory=lambda: str(uuid.uuid4())[:8])
+    group_id: str = ""
+    platform: str = ""
+    operation: str = ""
+    start_time: datetime = field(default_factory=datetime.now)
+    metadata: Dict[str, Any] = field(default_factory=dict)
+
+    # Timing data
+    _checkpoints: Dict[str, datetime] = field(default_factory=dict, init=False)
+
+    def checkpoint(self, name: str) -> None:
+        """
+        Record a timing checkpoint.
+
+        Args:
+            name: Checkpoint name
+        """
+        self._checkpoints[name] = datetime.now()
+
+    def elapsed_ms(self, from_checkpoint: Optional[str] = None) -> float:
+        """
+        Get elapsed time in milliseconds.
+
+        Args:
+            from_checkpoint: Optional checkpoint to measure from
+
+        Returns:
+            Elapsed time in milliseconds
+        """
+        start = self.start_time
+        if from_checkpoint and from_checkpoint in self._checkpoints:
+            start = self._checkpoints[from_checkpoint]
+
+        delta = datetime.now() - start
+        return delta.total_seconds() * 1000
+
+    def to_dict(self) -> Dict[str, Any]:
+        """Convert trace context to dictionary."""
+        return {
+            "trace_id": self.trace_id,
+            "group_id": self.group_id,
+            "platform": self.platform,
+            "operation": self.operation,
+            "start_time": self.start_time.isoformat(),
+            "elapsed_ms": self.elapsed_ms(),
+            "metadata": self.metadata,
+            "checkpoints": {k: v.isoformat() for k, v in self._checkpoints.items()},
+        }
+
+    def __enter__(self) -> "TraceContext":
+        """Enter context manager."""
+        _current_trace.set(self)
+        return self
+
+    def __exit__(self, exc_type, exc_val, exc_tb) -> None:
+        """Exit context manager."""
+        _current_trace.set(None)
+
+    @classmethod
+    def current(cls) -> Optional["TraceContext"]:
+        """Get the current trace context."""
+        return _current_trace.get()
+
+    @classmethod
+    def get_or_create(
+        cls,
+        group_id: str = "",
+        platform: str = "",
+        operation: str = "",
+    ) -> "TraceContext":
+        """
+        Get current trace or create a new one.
+
+        Args:
+            group_id: Group identifier
+            platform: Platform name
+            operation: Operation name
+
+        Returns:
+            TraceContext instance
+        """
+        current = cls.current()
+        if current:
+            return current
+
+        return cls(
+            group_id=group_id,
+            platform=platform,
+            operation=operation,
+        )
+
+
+def get_trace_id() -> str:
+    """
+    Get current trace ID or generate a new one.
+
+    Returns:
+        Trace ID string
+    """
+    trace = TraceContext.current()
+    if trace:
+        return trace.trace_id
+    return str(uuid.uuid4())[:8]
+
+
+def with_trace(
+    group_id: str = "",
+    platform: str = "",
+    operation: str = "",
+):
+    """
+    Decorator to add trace context to a function.
+
+    Args:
+        group_id: Group identifier
+        platform: Platform name
+        operation: Operation name
+
+    Returns:
+        Decorated function
+    """
+
+    def decorator(func):
+        async def wrapper(*args, **kwargs):
+            with TraceContext(
+                group_id=group_id,
+                platform=platform,
+                operation=operation or func.__name__,
+            ):
+                return await func(*args, **kwargs)
+
+        return wrapper
+
+    return decorator