Prompt: add Fred Swaniker voice & tone calibration to system prompt

Prompt: lead with the relevant link when partial info is available, not with 'I don't know'

Wire Google Sheet knowledge base into Claude RAG

Phase 3: streaming chat via SSE with prompt caching preserved

Phase 3: prompt caching, history cap, essay coach endpoint

Replace fabricated knowledge base with verified, source-linked content

Tighten Claude system prompt: no emoji headings, sparse markdown

Phase 2: Claude RAG, document upload, Tavily opportunities