fix: map README links to actual filenames and update section READMEs

- Fix all broken links in root README (partner-channel-strategy → Ideal Customer Profile, etc.)
- Add code/ directory to repo structure tree
- Update status table: Legal ✅, MCP Server ✅ MVP
- Rewrite section READMEs with actual file inventories:
  docs/engineering/, docs/gtm/, docs/investors/, docs/legal/

docs/engineering/README.md

@@ -1,5 +1,22 @@
-# Engineering Folder — geolocal.io
+# Engineering — geolocal.io
 
-Architecture overview, MCP server design, data model, Cal.com integration, telemetry pipeline, MVP scope per vertical.
+Architecture, technical roadmap, and implementation.
 
-Every technical decision must trace back to NORTH_STAR.md.
+## Files
+
+| File | Description |
+|------|-------------|
+| [Technical Roadmap](./technical%20roadmap.md) | 12-week phased plan: MVP → V1 → Scale |
+
+## Code
+
+The MCP server implementation lives in the repo root [`code/`](../../code/) directory:
+
+- **`src/index.ts`** — Server entry point (stdio transport)
+- **`src/mcp-server.ts`** — Tool registration (5 MCP tools)
+- **`src/tools/`** — Individual tool implementations
+- **`src/db/`** — PostgreSQL schema + seed data
+- **`src/manifest-generator.ts`** — `/.well-known/mcp-server` JSON manifest
+- **`railway.json`** + **`Dockerfile`** — Deployment config
+
+Every technical decision must trace back to [NORTH_STAR.md](../../NORTH_STAR.md).