feat: generalized agent runner and MCP error detection

[daniloc]

Changes:

agent-interface.ts

• Signals to the CLI when MCP or a specific resource is missing (AgentSignals)
• Logs errors to PostHog when these things happen (AgentErrorType)
• Adds explicit tool permissions for bash commands (ALLOWED_BASH_PREFIXES)
• Upgrades to Opus 4.5

agent-runner.ts

Provides a universal interface for running integrations across frameworks using @posthog/agent, piping appropriate feedback to the CLI output. Largely abstracted from the existing Next.js agent implementation. Uses framework-config.ts to set up the run.

nextjs-wizard-agent.ts now creates a config and fires the agent runner.

oauth.ts

The OAuth page is supposed to close itself but it often doesn't, so I made some nicer CSS for it.

Testing

Tested and working locally: package installs work and everything proceeds the way we expect from the existing wizard v2 behavior.

[wiz-7ad640923b]

Wiz Scan Summary

Scanner	Findings
Vulnerabilities	2  3  3
Sensitive Data	-
Secrets	-
IaC Misconfigurations	-
SAST Findings	-
Total	2  3  3

View scan details in Wiz

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[sarahxsanders]

definitely still learning all things wizard, but taking a look at these PRs is helpful for my sponge brain to absorb :] left a few comments that are non-blocking

[edwinyjlim]

the agent runner is noiiiice

[gewenyu99]

Dude this is so coool. Makes me wanna clear my calendar and join you in hacking on this.

This is starting to look super clean