fix: add junie to tarball build pipeline (#2541)

Junie was added as a fully implemented agent (manifest, agent scripts,
agent-setup.ts) but the packer/tarball pipeline was never updated.
This meant the nightly agent-tarballs workflow could not build a
pre-built tarball for Junie, forcing all deployments to do a live
npm install.

- Add junie entry to packer/agents.json (tier: node, @jetbrains/junie-cli)
- Add junie to capture-agent.sh allowlist and path-capture case
  (npm-based, same as codex/kilocode — captures /root/.npm-global/)

Agent: code-health

Co-authored-by: B <6723574+louisgv@users.noreply.github.com>
Co-authored-by: Claude Sonnet 4.5 <noreply@anthropic.com>

packer/agents.json

@@ -42,5 +42,11 @@
     "install": [
       "curl -fsSL https://raw.githubusercontent.com/NousResearch/hermes-agent/main/scripts/install.sh | bash || [ -f ~/.local/bin/hermes ]"
     ]
+  },
+  "junie": {
+    "tier": "node",
+    "install": [
+      "mkdir -p ~/.npm-global/bin && npm install -g --prefix ~/.npm-global @jetbrains/junie-cli"
+    ]
   }
 }