chore: remove web-harness and update rollup to fix vulnerability (#463)

* fix: prevent spurious agent startup in dev mode and remove tiktoken dep

When running `agentcore dev` with multiple agents, useDevServer would
start the first agent's server before the user selected one, because
getDevConfig defaults to agents[0] when agentName is undefined. Guard
config resolution on agentName being set so the server only starts
after explicit selection.

Also remove tiktoken from the LangChain template dependencies as the
package no longer resolves correctly.

* chore: remove web-harness and update rollup to fix vulnerability

Author: tejaskash

eslint.config.mjs

@@ -83,7 +83,6 @@ export default tseslint.config(
       'node_modules',
       'src/assets',
       'src/schema/llm-compacted',
-      'web-harness',
       '.agentcore',
       '**/.agentcore/**',
       '.venv',

package-lock.json

@@ -56,17 +56,6 @@ The TUI is defined using ink, a library that converts React definitions to termi
 
 Ink supports a subset of React features and components should be directly imported from ink.
 
-## Testing UI changes E2E
-
-At the top level `web-harness/` directory a shim over Ink, as well as a mock of Node API and CLI business logic is
-defined. By running the vite local host dev server, a web app based on the same visual source of truth as the terminal
-is hosted. Always launch a web-harness web server and use the browser MCP tool to test changes E2E. Create mocks as
-appropriate to test the relevant surface area.
-
-If start up issues are encountered, read the console error to troubleshoot bugs and update the harness.
-
-## Dev Server Architecture
-
 The `dev` command uses a strategy pattern with a `DevServer` base class and two implementations:
 
 - **CodeZipDevServer**: Runs uvicorn locally with Python venv hot-reload