feat: [Phase 3] Schema cache (FTS5) + FinOps SQL templates

[anandgupta42]

Phase 3: Schema Cache + FinOps

Parent: #214
Depends on: Phase 2

What

Port the SQLite schema cache (FTS5) and all 10 FinOps SQL template modules from Python to TypeScript.

Sub-tasks

• native/schema/cache.ts — better-sqlite3 with FTS5, port DDL from Python
• native/schema/pii-detector.ts — pattern matching + altimateCore.classifyPii()
• native/schema/tags.ts — Snowflake TAG_REFERENCES queries
• native/finops/credit-analyzer.ts — SQL templates verbatim from Python
• native/finops/query-history.ts
• native/finops/warehouse-advisor.ts
• native/finops/unused-resources.ts
• native/finops/role-access.ts
• Register 16 dispatcher methods (6 schema + 10 finops)
• Unit tests for SQL template generation per warehouse type
• Schema cache search/index integration tests

[anandgupta42]

Completed in PR #221.