feat: initial alpha scaffold — FastAPI + MCP + pgvector

Implements v0.0.1 of OpenBrain:

- FastAPI REST API (capture, search, recent, stats) with Bearer auth
- MCP server (streamable HTTP at /mcp) exposing all 4 tools
- pgvector schema (vector(1024) for bge-m3)
- asyncpg connection pool with lazy init + graceful close
- Ollama embedding client with fallback (stores thought without vector if Ollama unreachable)
- Woodpecker CI pipeline (lint + kaniko build + push to Gitea registry)
- Portainer/Swarm deployment compose
- Mosaic framework files: AGENTS.md, PRD.md, TASKS.md, scratchpad

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

docs/scratchpads/v001-build.md

@@ -0,0 +1,41 @@
+# Scratchpad: v0.0.1 Build
+
+**Date**: 2026-03-02
+**Objective**: Build and deploy alpha OpenBrain service
+
+## Plan
+
+1. [x] Scaffold project structure
+2. [x] Core brain operations (capture, search, recent, stats)
+3. [x] FastAPI REST + MCP server (single process)
+4. [x] pgvector schema
+5. [x] Dockerfile
+6. [x] Portainer compose
+7. [x] Woodpecker CI pipeline
+8. [x] Mosaic framework files (AGENTS.md, PRD.md, TASKS.md)
+9. [ ] Initial commit + push
+10. [ ] Woodpecker secrets verified
+11. [ ] DNS + Traefik config for brain.woltje.com
+12. [ ] Host init.sql copy + Portainer stack deploy
+13. [ ] Smoke test via MCP
+
+## Decisions
+
+- Single Python process for REST + MCP (avoids 2-container overhead for alpha)
+- Streamable HTTP MCP transport (not stdio — deployed service, needs HTTP)
+- bge-m3 via existing Ollama at 10.1.1.42 (verified live)
+- vector(1024) — bge-m3 native, no padding
+- Graceful fallback: thoughts stored without embedding if Ollama unreachable
+- pgvector/pgvector:pg17 official image — no custom build needed
+
+## Blockers / Notes
+
+- Woodpecker CI secrets (GITEA_USERNAME, GITEA_TOKEN) must be set for build pipeline
+- DNS record for brain.woltje.com needs to be created
+- Init SQL must be on host at /opt/openbrain/init.sql before first Portainer deploy
+- MCP auth: headers passed via Claude Code settings — confirm MCP SDK accepts headers on streamable HTTP
+
+## Risks
+
+- MCP streamable HTTP transport is newer spec — need to verify Claude Code supports it
+  - Fallback: switch to SSE transport (mcp.server.sse.SseServerTransport)