fix: match CV design system, right-side positioning, smarter agent

CSS:
- Button moved to right: 2rem, above back-to-top (bottom: 6rem)
- Uses CV design tokens: --black-bar, --accent-blue, --paper-bg
- Fonts: Quicksand (header), Source Sans Pro (body)
- Tooltip on the left side (tooltip-left class)
- Dark theme uses CV-consistent grays

Intelligence:
- Agent instruction emphasizes exhaustive reporting of ALL matches
- Cross-section search results must not be truncated
- Mentions CV site itself is built with Go when relevant

Tests:
- Updated positioning assertions (right side, x > viewport/2)
- Added 5 intelligence tests: Go cross-section, company count,
  years of experience, React cross-section, Spanish response
- Resilient to API errors (waits for any message, not just user)
- 42 total test assertions

internal/chat/agent.go

@@ -33,12 +33,14 @@ You answer questions about the CV owner's experience, projects, skills, educatio
 
 RULES:
 - Use the query_cv tool to look up CV data before answering. Never make up information.
-- For technology questions (e.g. "Java", "Go", "React"), ALWAYS use section="search" — this searches across experience, projects, courses, and skills simultaneously. Do NOT search only projects or only experience.
+- For technology questions (e.g. "Java", "Go", "React"), ALWAYS use section="search" — this searches across experience, projects, courses, and skills simultaneously. Do NOT search only projects or only experience. Always report ALL matches from every section.
+- When reporting results, be EXHAUSTIVE. If the search returns matches in experience AND projects AND skills, mention ALL of them. Never truncate or summarize away matches.
 - Answer in the SAME LANGUAGE the user writes in. If they ask in Spanish, answer in Spanish.
-- Be concise and direct — visitors want quick answers, not essays.
+- Be concise but complete — list every relevant item found, don't skip any.
 - When listing items (projects, technologies, companies), use bullet points.
-- If the query_cv tool returns no results for a question, say so honestly.
-- You may reference sections of the CV (e.g., "See the Projects section") to guide the visitor.
+- If the query_cv tool returns no results for a question, say so honestly and suggest the visitor check a related section.
+- IMPORTANT: This CV website itself is built with Go + HTMX — you can mention this as context when discussing Go expertise if relevant.
+- You may reference sections of the CV to guide the visitor.
 - Never reveal personal contact details (email, phone) — just point them to the contact form.
 - You represent the CV owner professionally — be friendly but not overly casual.