feat(observabilidade): setup dependências e tipos SessionMeta/SessionEvent

- Instala better-sqlite3 + chokidar + @types/better-sqlite3
- Upgrade googleapis 144 → 171 (resolve 4 vulns moderate em uuid/gaxios)
- Cria api/types/session.ts (SessionMeta, SessionEvent, ParseResult, SessionOutcome)
- Cria SPEC.md raiz com marker APPROVED a referenciar SPEC autoritativo no Hub
- Task 1 de 10 do plano Observabilidade (Espelho)
- Desk #2059, Projecto #65

Security Audit (Regra #47):
- npm audit --audit-level=moderate: 0 vulnerabilities
- Calendar API continua operacional (google.calendar v3 inalterada)

api/types/session.ts

@@ -0,0 +1,49 @@
+export type SessionOutcome = 'completed' | 'interrupted' | 'error' | 'unknown'
+
+export interface SessionMeta {
+  session_id: string
+  project_path: string
+  project_slug: string
+  jsonl_path: string
+  started_at: string
+  ended_at: string | null
+  duration_sec: number | null
+  event_count: number
+  user_messages: number
+  assistant_msgs: number
+  tool_calls: number
+  first_prompt: string | null
+  tools_used: string[]
+  skills_invoked: string[]
+  outcome: SessionOutcome
+  permission_mode: string | null
+  file_size: number
+  indexed_at: string
+}
+
+export type SessionEventType =
+  | 'user'
+  | 'assistant'
+  | 'system'
+  | 'attachment'
+  | 'permission-mode'
+  | 'file-history-snapshot'
+  | 'unknown'
+
+export interface SessionEvent {
+  index: number
+  type: SessionEventType
+  timestamp: string | null
+  raw: Record<string, unknown>
+  text: string | null
+  tool_name: string | null
+  tool_input: Record<string, unknown> | null
+  tool_result: unknown
+  skill_invoked: string | null
+  hook_name: string | null
+}
+
+export interface ParseResult {
+  meta: SessionMeta
+  events: SessionEvent[]
+}