fix: make the shared package a devDependency and drop stale paths

packages/builder is publishable (private:false) but depended on the
private workspace package at runtime - a published manifest would
advertise an unresolvable dependency. tsup's noExternal inlines it into
the bundle, so devDependencies is the correct home.

Also removes the root tsconfig.json, which still pointed at the deleted
src/, and corrects two README paths the move invalidated.

README.md

@@ -128,7 +128,7 @@ Add to your Claude Desktop MCP config (`claude_desktop_config.json`):
   "mcpServers": {
     "vector": {
       "command": "node",
-      "args": ["/path/to/vector-mcp-server/build/index.js"],
+      "args": ["/path/to/vector-mcp-server/packages/builder/build/index.js"],
       "env": {
         "VECTOR_OGMIOS_URL": "https://ogmios.vector.testnet.apexfusion.org",
         "VECTOR_SUBMIT_URL": "https://submit.vector.testnet.apexfusion.org/api/submit/tx",
@@ -188,11 +188,11 @@ npm run test:smoke
 Builds the server, boots it, and asserts the exposed tool inventory matches the checked-in snapshot. No wallet, no external network. CI runs this and `test:unit` on every PR.
 
 ```bash
-echo "your mnemonic words here" > mnemonic.txt
+echo "your mnemonic words here" > packages/builder/mnemonic.txt
 npm run test:integration
 ```
 
-Requires `mnemonic.txt` in the repo root containing a **funded Vector testnet** mnemonic. Covers the core tools end-to-end against Vector testnet, including the full agent lifecycle: register, discover, profile, update, transfer, message, and deregister. Never runs in CI.
+Requires `mnemonic.txt` in `packages/builder/` containing a **funded Vector testnet** mnemonic. Covers the core tools end-to-end against Vector testnet, including the full agent lifecycle: register, discover, profile, update, transfer, message, and deregister. Never runs in CI.
 
 ## Architecture