feat: add poly wren command for AI-assisted editing

[Ruari-Phipps]

Summary

Adds poly wren — an interactive chat CLI against the Wren SSE developer endpoint. Wren works remotely on a branch; the CLI streams its work live, switches the local project to wren-created branches, and pulls applied changes automatically.

Motivation

The platform now exposes a PAT-authenticated SSE endpoint for Wren (POST /v1/studio-assistant/turn). This brings AI-assisted agent editing into the ADK workflow: describe a change in natural language, watch wren plan/build/test it remotely, and end up with the result pulled into the local workspace.

Changes

• poly wren interactive REPL: multiline prompt (Enter sends, Ctrl+J newline), live-rendered markdown replies, spinner narration from tool ui_descriptions, header panel, session resume via --session-id
• SSE client (handlers/wren_api.py) follows the full run chain — mid-chain suspended completes, subagent frames, and auto-answered input gates don't end the turn
• Branch handling: refuses to start with local uncommitted changes (--force to override); switches the local project when wren creates/switches branches (name + ID shown)
• Pull policy: pulls after turns where wren applied changes (✔ Applied N changes…), once more at exit if needed; --no-pull disables
• Plan and final-report cards render as markdown panels; mermaid blocks get clickable mermaid.live links
• Auto-mode gates display the question + auto-chosen answer; genuine gates prompt via questionary
• --json -m single-shot mode emitting one machine-readable object
• Hidden --replay <conv.json> dev harness: renders downloaded conversation exports through the real renderer for offline UX iteration
• Hidden poly glot alias
• Busy-retry: a new prompt sent while a suspended run is still working waits (409 retry loop, up to ~10 min)

Test strategy

• Added/updated unit tests (46 new tests: event rendering, SSE terminal semantics, apply parsing, replay adapter, retry loop, mermaid links)
• Manual CLI testing (poly wren, poly wren --replay)
• Tested against a live Agent Studio project (multi-turn build session on ruari-ws)

Checklist

• ruff check . and ruff format --check . pass
• pytest passes (827 passed)
• No breaking changes to the poly CLI interface (or migration path documented)
• Commit messages follow conventional commits

Screenshots / Logs

╭──────────── Wren ─────────────╮
│  Workspace  ruari-ws          │
│  Project    PROJECT-F9T2XAXJ  │
│  Branch     ADK-40881-ae45    │
╰────────────────────────────────╯
  Enter send · Ctrl+J newline · /exit quit

You: I want to build 10 faqs for a general hotel agent
  ? Should I create 10 common hotel FAQs (check-in/out times, parking, …)?
  → auto-answered: Yes, those topics sound good
⠋ Planning 10 hotel FAQ topics…
╭─ Plan: Hotel FAQ Topics ──────────────────────────╮
│ …rendered markdown plan…                          │
╰───────────────────────────────────────────────────╯
✔ Applied 23 changes to the branch (23 modified)
  Pulling changes to local workspace… done.

🤖 Generated with Claude Code

[github-actions]

Coverage Report

Base (main)	PR	Change
73.0%	71.8%	-1.2% ⚠️

Changed file coverage

File	Coverage	Change
poly/cli.py	78.8%	+0.3% ✅