test: add tests for presets.ts bundle helper functions

[George-iam]

The presets module (src/presets.ts) provides helper functions that convert preset bundles into typed domain objects: bundlesToDecisions, bundlesToMemories, bundlesToDeployChecklists, bundlesToConfigDefaults, and applyPresetSafetyRules. These are pure functions that take bundle IDs and return structured data, making them easy to test. Currently there are no dedicated tests for these helpers.

Relevant files:

• src/presets.ts — the module to test
• src/types.ts — Decision, Memory, SafetyRules types
• test/ — place the new test file here as presets.test.ts

Suggested test cases:

• getPresetBundle returns correct bundle for known ID
• getPresetBundle returns undefined for unknown ID
• bundlesToDecisions generates sequential D-NNN IDs starting from given startId
• bundlesToDecisions deduplicates by slug across multiple bundles
• bundlesToMemories sets source to "preset" and sessionId to null
• bundlesToDeployChecklists merges staging and production items from multiple bundles
• applyPresetSafetyRules unions deny lists without duplicates
• bundlesToConfigDefaults merges config from multiple bundles (later wins)

Acceptance criteria:

• New file test/presets.test.ts with at least 10 tests
• All tests pass with npm test