fix: address pre-release review findings for v0.5.15 - #580

What does this PR do?

Addresses all findings from 5-persona pre-release validation for v0.5.15. Fixes dead code, undefined display bugs, adds missing driver security tests, and fills documentation gaps.

Type of change

• Bug fix (non-breaking change which fixes an issue)
• Tests
• Documentation

Issue for this PR

Closes #579

How did you verify your code works?

• All 24 new driver security tests pass (DuckDB retry, MongoDB blocking, PG/Redshift validation, registry hints)
• 832/832 simulation suite tests pass
• 28/28 feature discovery e2e tests pass
• 125/125 telemetry tests pass
• Typecheck passes (bun turbo typecheck)
• Marker guard passes (bun run script/upstream/analyze.ts --markers --base main --strict)

Checklist

• I have added tests for my changes
• I have updated the documentation accordingly
• My changes generate no new warnings

Changes

Code fixes:

• Remove duplicate altimate_change end markers in prompt.ts (lines 812, 962)
• Fix classifySkillTrigger() to return "unknown" for unexpected triggers (was dead code)
• Remove unused "schema_not_indexed" from feature_suggestion telemetry type

Undefined display bugs (7 files):

• sql-translate.ts: null guards on source_dialect/target_dialect
• dbt-manifest.ts: null guards on model.name, source.source_name, source.name + propagate result.error to metadata
• dbt-lineage.ts: null guards on model_name, confidence
• altimate-core-column-lineage.ts / altimate-core-track-lineage.ts: null guards on edge.source/edge.target

Test credential cleanup:

• Replace password: "secret" → "test-fake-password" in 3 test fixtures

New driver security tests (24 tests):

• DuckDB: wrapDuckDBError wrapping, lock retry with READ_ONLY fallback, in-memory no-retry
• MongoDB: $out/$merge write stage blocking, $function/$accumulator JS execution blocking, safe pipeline passthrough
• PostgreSQL: password type validation, statement_timeout with valid/NaN/negative values
• Redshift: password type validation
• Registry: ClickHouse/Cassandra/CockroachDB/TimescaleDB friendly hints, unknown type error

Documentation:

• DuckDB: concurrent access auto-retry note in warehouses.md
• MongoDB: blocked operators warning in warehouses.md
• New "Unsupported Databases" section with workaround table

🤖 Generated with Claude Code

Summary by CodeRabbit

• Documentation

  • Added DuckDB concurrent-write guidance, MongoDB operator restrictions, and an “Unsupported Databases” section with workarounds.

• Bug Fixes

  • Improved resilience across lineage, manifest, and translation outputs to handle missing/undefined fields gracefully.

• Tests

  • Added comprehensive security and validation tests for database drivers and connection handling.

• Chores

  • Refined telemetry event payloads and adjusted trigger-classification fallback.