refactor: improve type safety by removing 'as any' casts

Created database.ts with proper database result types and replaced 38+ 'as any' casts throughout the codebase with proper type annotations.

Changes:
- Created src/types/database.ts with TableColumnInfo, IndexInfo, and database record types
- Fixed all type casts in SessionStore.ts (migrations, query results)
- Fixed type casts in SessionSearch.ts, SettingsManager.ts, SettingsRoutes.ts
- Improved MCP server JSON schema typing

All builds pass and worker service runs successfully.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

src/types/database.ts

@@ -0,0 +1,138 @@
+/**
+ * TypeScript types for database query results
+ * Provides type safety for better-sqlite3 query results
+ */
+
+/**
+ * Schema information from sqlite3 PRAGMA table_info
+ */
+export interface TableColumnInfo {
+  cid: number;
+  name: string;
+  type: string;
+  notnull: number;
+  dflt_value: string | null;
+  pk: number;
+}
+
+/**
+ * Index information from sqlite3 PRAGMA index_list
+ */
+export interface IndexInfo {
+  seq: number;
+  name: string;
+  unique: number;
+  origin: string;
+  partial: number;
+}
+
+/**
+ * Table name from sqlite_master
+ */
+export interface TableNameRow {
+  name: string;
+}
+
+/**
+ * Schema version record
+ */
+export interface SchemaVersion {
+  version: number;
+}
+
+/**
+ * SDK Session database record
+ */
+export interface SdkSessionRecord {
+  id: number;
+  claude_session_id: string;
+  sdk_session_id: string | null;
+  project: string;
+  user_prompt: string | null;
+  started_at: string;
+  started_at_epoch: number;
+  completed_at: string | null;
+  completed_at_epoch: number | null;
+  status: 'active' | 'completed' | 'failed';
+  worker_port?: number;
+  prompt_counter?: number;
+}
+
+/**
+ * Observation database record
+ */
+export interface ObservationRecord {
+  id: number;
+  sdk_session_id: string;
+  project: string;
+  text: string | null;
+  type: 'decision' | 'bugfix' | 'feature' | 'refactor' | 'discovery' | 'change';
+  created_at: string;
+  created_at_epoch: number;
+  title?: string;
+  concept?: string;
+  source_files?: string;
+  prompt_number?: number;
+  discovery_tokens?: number;
+}
+
+/**
+ * Session Summary database record
+ */
+export interface SessionSummaryRecord {
+  id: number;
+  sdk_session_id: string;
+  project: string;
+  request: string | null;
+  investigated: string | null;
+  learned: string | null;
+  completed: string | null;
+  next_steps: string | null;
+  created_at: string;
+  created_at_epoch: number;
+  prompt_number?: number;
+  discovery_tokens?: number;
+}
+
+/**
+ * User Prompt database record
+ */
+export interface UserPromptRecord {
+  id: number;
+  claude_session_id: string;
+  prompt_number: number;
+  prompt_text: string;
+  created_at: string;
+  created_at_epoch: number;
+}
+
+/**
+ * Latest user prompt with session join
+ */
+export interface LatestPromptResult {
+  id: number;
+  claude_session_id: string;
+  sdk_session_id: string;
+  project: string;
+  prompt_number: number;
+  prompt_text: string;
+  created_at_epoch: number;
+}
+
+/**
+ * Observation with context (for time-based queries)
+ */
+export interface ObservationWithContext {
+  id: number;
+  sdk_session_id: string;
+  project: string;
+  text: string | null;
+  type: string;
+  created_at: string;
+  created_at_epoch: number;
+  title?: string;
+  concept?: string;
+  source_files?: string;
+  prompt_number?: number;
+  discovery_tokens?: number;
+}