Add neuron-dev-setup: one-command CORE dev stack onboarding installer

Scaffolds a reproducible, idempotent installer that stands up the four native
launchd core services (soul :7770, engram :8742, mcp-wrapper :17779,
mcp-proxy :7779), seeds a fresh engram with the genesis identity via forge, and
installs the Claude Code config (neuron agent + core hooks + local MCP). Fully
templated to the invoking user's $HOME; Anthropic key prompted and stored in
Keychain; no secrets committed. Personal automations and synapse-dependent hooks
excluded from core.

neuron-dev-setup/templates/claude/settings.core.json

@@ -0,0 +1,36 @@
+{
+  "//": "Core Neuron Claude Code settings installed by neuron-dev-setup. If you",
+  "//2": "already have a ~/.claude/settings.json, install.sh merges the hooks below",
+  "//3": "into it rather than overwriting. Only the CORE dev-stack hooks are wired.",
+  "//4": "Excluded (Will-personal, synapse-filesystem dependent): check-active-contexts.sh,",
+  "//5": "require-execution-context.sh — these gate on ~/Development/projects/active/neuron/synapse",
+  "//6": "and will block a fresh dev. engram-mirror.py is optional (needs the neuron MCP up).",
+  "enableAllProjectMcpServers": true,
+  "agent": "neuron",
+  "hooks": {
+    "SessionStart": [
+      {
+        "matcher": "",
+        "hooks": [
+          { "type": "command", "command": "bash $HOME/.claude/hooks/neuron-self-load.sh" }
+        ]
+      }
+    ],
+    "PreToolUse": [
+      {
+        "matcher": "Agent",
+        "hooks": [
+          { "type": "command", "command": "bash $HOME/.claude/hooks/neuron-agent-preamble.sh" }
+        ]
+      }
+    ],
+    "PreCompact": [
+      {
+        "matcher": "",
+        "hooks": [
+          { "type": "command", "command": "bash $HOME/.claude/hooks/pre-compact.sh" }
+        ]
+      }
+    ]
+  }
+}