docs: update changelog, readme, and docs for v3.5.0

- Add CHANGELOG.md entry for v3.5.0 with all PR #336 changes
- Update README.md: version 3.5.0, agent-agnostic examples, marketplace
  pipeline, SPA discovery
- Update CLAUDE.md: AgentClient architecture, 40 MCP tools, new modules
- Update docs/: UML architecture, MCP reference (40 tools, new tool
  categories), enhancement modes (multi-provider/multi-agent), FAQ
- Update src/skill_seekers/mcp/README.md: accurate tool count and paths

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

docs/FAQ.md

@@ -460,9 +460,9 @@ skill-seekers upload output/react-claude.zip --target claude
 
 AI enhancement transforms basic skills (2-3/10 quality) into production-ready skills (8-9/10 quality) using LLMs.
 
-**Two Modes:**
-1. **API Mode:** Direct Claude API calls (fast, costs ~$0.15-0.30)
-2. **LOCAL Mode:** Uses Claude Code CLI (free with your Max plan)
+**Two Modes (via AgentClient):**
+1. **API Mode:** Multi-provider AI API calls -- Anthropic, Moonshot/Kimi, Gemini, OpenAI (fast, costs ~$0.15-0.30)
+2. **LOCAL Mode:** Any supported coding agent -- Claude Code, Kimi, Codex, Copilot, OpenCode, or custom (free with agent subscription)
 
 **What it improves:**
 - Better organization and structure