Nests: team rooms with core crows and borrowing

- Server: nests API, persistence, core-first picking, borrowed flag
  (built by the backend agent against EVENTS.md; tests pass with -race)
- UI: nests in the sidebar, one feed per nest, header shows the core
  team, New nest dialog, borrowed crows labeled, per-nest waiting count
- start.command: one-click local server in controlled mode (mock crows,
  localhost only, state in .crows/)

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01UQnSw4RRWp8uqpj3nsnnXF

start.command

@@ -0,0 +1,22 @@
+#!/bin/bash
+# So Many Crows: local test server.
+# Double-click to start. Close this window (or Ctrl-C) to stop.
+#
+# Controlled by default:
+#   - offline mock crows (no API key used, no cost, no network calls)
+#   - listens on this Mac only (127.0.0.1:8080)
+#   - all state lives in this folder's .crows/ (delete it to start fresh)
+# From Terminal, `./start.command --real` uses real Claude crows (needs ANTHROPIC_API_KEY).
+cd "$(dirname "$0")" || exit 1
+xattr -d com.apple.quarantine ./crows 2>/dev/null
+chmod +x ./crows
+if [ "$1" != "--real" ]; then
+  unset ANTHROPIC_API_KEY
+  echo "Controlled mode: offline mock crows."
+fi
+if lsof -iTCP:8080 -sTCP:LISTEN >/dev/null 2>&1; then
+  echo "Something is already using port 8080. Stop it first."
+  exit 1
+fi
+(sleep 1; open "http://127.0.0.1:8080") &
+exec ./crows serve -addr 127.0.0.1:8080