feat(web): interactive plan creation from web dashboard

[melonamin]

Summary

Implements interactive plan creation in the web dashboard, allowing users to create plans through a browser-based workflow instead of CLI-only.

Closes #32

Changes

• WebInputCollector: Channel-based input collector that blocks on AskQuestion() until web client submits an answer via /api/answer
• PlanRunner: Orchestrates plan creation sessions - starts Claude with plan prompt, handles Q&A loop, manages session lifecycle
• Session resume: Detect and resume interrupted plan sessions from progress files
• Q&A JSON parsing: Handle multi-line output with log prefixes (timestamps split across lines)
• UI: "New Plan" modal with directory selection (recent dirs from config) and description input
• SSE events: Real-time question/answer streaming to browser

Architecture

Uses channel-based coordination (option 1 from the issue):

1. PlanRunner.StartPlan() launches Claude with plan creation prompt
2. When QUESTION signal detected, WebInputCollector.AskQuestion() blocks on channel
3. SSE emits question/options to browser
4. Browser renders modal, user selects answer
5. POST /api/answer unblocks the runner
6. Loop continues until PLAN_READY signal

For directory selection (option C): Uses recent directories from config, user can also type custom path.

Test plan

• Unit tests for WebInputCollector, PlanRunner, resumable detection
• Server handler tests for new endpoints
• Test coverage at 88% for web package
• E2E: Start plan from web UI, answer questions, verify plan file created
• E2E: Interrupt session, resume from web UI

[melonamin]

@umputun please play with the UI, when you have time, and tell me how you feel about it.

[umputun]

found these issues on first try:

1. UX: --serve alone fails - without --watch, errors "no plans found". if someone wants to create their first plan via web UI, they shouldn't need watch dirs. suggest:

   • treat --serve alone as minimal dashboard mode (current dir as default watch)
   • or give helpful error: "use --watch to start dashboard"

2. UI: empty status badge visible - renders as empty pill when no session active. should hide when empty:

   .status-badge:empty { display: none; }

haven't done deep code review yet - this is just from trying to run it.

[melonamin]

Addressed both.

I think that the mental model behind --serve and --serve --watchdir can be a bit confusing.

My main and only use case is that I always run it as --serve --watchdir ~/Developer, basically like a daemon. Then, all ralphex sessions are picked up automatically.

I understand the appeal of having an ad-hoc --serve, but if it were my product, I would probably sacrifice the flexibility for simplicity, both in terms of the mental model and the code.

Your call, obviously.