Feature/swarm 73 build a web search pipeline

[theuvargas]

This pull request implements most features from issue #12 and its subissues.

• Integrates Scraper and Navigator into the main pipeline with a rule-based query enhancer. If the evidence isn't strong enough, it uses the rules defined in the decideEnhancement function to decide to use either the scraper or the navigator.
• URL deduplication: prevents the same URL from being processed more than once by the pipeline
• LLM gate picker: uses a LLM to select the most promising URLs for processing
• 3 tests: one for the validation (of a single example), one for the enhancement, and one end-to-end test with 10 fixed predictions from the DB

[linear]

SWARM-73 Build a Web Search Pipeline