feat: neon-init v2 agent-driven state machine

Redesigns neon-init as a stateless state machine where each CLI invocation
returns a typed JSON response with a `nextAction` that tells the agent
exactly what to do next. Key changes:

- Orchestrator inspects filesystem (MCP config, skills, DATABASE_URL) to
  skip phases that are already satisfied — no unnecessary round-trips
- Phase handlers for auth, setup, getting-started, db, neon-auth,
  migrations, mcp, skills, and status as composable subcommands
- `responseMapping` supports inline `{ action: NextAction }` to eliminate
  CLI round-trips (e.g. auth OAuth launches directly after user confirms)
- Auth verified responses use `run_neon_init` instead of `complete` to
  prevent agents from getting distracted by neonctl output
- `ensureSkillsUpToDate()` with 12-hour freshness window — called from
  phase handlers, skips if skills-lock.json or global skills dir is recent
- Agent detection via TTY: IDE env vars + non-TTY stdin = agent invocation,
  IDE env vars + TTY stdin = human in terminal → interactive mode
- Interactive mode with clack prompts, Neon green branding via picocolors
  patch, org/project selection, .neon context file
- Extension install fallback chain: marketplace → VSIX download (corporate
  proxy or Open VSX) → manual instructions
- Input validation (assertSafeId) for org/project IDs in shell commands
- Filesystem inspection module (inspect.ts) shared by orchestrator, setup,
  and status phases
- 95 tests across 11 test files

Co-authored-by: Isaac

Author: jeff-at-neon

packages/init/.gitignore

@@ -0,0 +1,5 @@
+src/lib/build-config.ts
+.agents/
+.claude/skills/
+skills-lock.json
+bin/

packages/init/package.json

@@ -34,10 +34,12 @@
 		"package.json"
 	],
 	"scripts": {
-		"build": "tsc --noEmit && tsdown",
+		"build": "node scripts/set-vsx-gallery.mjs && tsc --noEmit && tsdown",
+		"build:internal": "node scripts/set-vsx-gallery.mjs https://cursor-vsx-proxy.cloud.databricks.com/gallery && tsc --noEmit && tsdown",
+		"pretest": "node scripts/set-vsx-gallery.mjs",
 		"test": "vitest --passWithNoTests",
 		"test:ci": "vitest run --passWithNoTests",
-		"tsc": "tsc"
+		"tsc": "node scripts/set-vsx-gallery.mjs && tsc"
 	},
 	"devDependencies": {
 		"@types/node": "catalog:",
@@ -52,6 +54,7 @@
 		"@clack/prompts": "0.10.1",
 		"add-mcp": "^1.5.1",
 		"execa": "^9.5.2",
+		"picocolors": "^1.1.1",
 		"yargs": "^18.0.0",
 		"yoctocolors": "^2.1.2"
 	},

packages/init/scripts/set-vsx-gallery.mjs

@@ -0,0 +1,11 @@
+// Generates src/lib/build-config.ts with the VSX gallery URL baked in.
+// Usage:
+//   node scripts/set-vsx-gallery.mjs                          → empty (external release)
+//   node scripts/set-vsx-gallery.mjs https://proxy.example.com/gallery  → baked in (internal)
+import { writeFileSync } from "node:fs";
+
+const url = process.argv[2] || "";
+writeFileSync(
+	"src/lib/build-config.ts",
+	`// Auto-generated by scripts/set-vsx-gallery.mjs — do not edit\nexport const INTERNAL_VSX_GALLERY = ${JSON.stringify(url)};\n`,
+);