chore(template): wire plugins — ecc/molecule-dev/superpowers default + browser-automation for research & UIUX

Currently no workspace in the molecule-dev template installs any of the
four available plugins (browser-automation, ecc, molecule-dev, superpowers).
Agents run without coding guardrails, codebase conventions, or debugging
discipline unless a plugin is installed per-workspace via the runtime
POST /workspaces/:id/plugins endpoint — which isn't happening.

Changes:

1. defaults.plugins: [ecc, molecule-dev, superpowers]
   - ecc: "Everything Claude Code" — coding standards, API design,
     deep research, security review, TDD workflow, node guardrails
   - molecule-dev: project-specific conventions, past bugs, review-loop skill
   - superpowers: systematic debugging, TDD, plan writing/execution,
     verification-before-completion
   All three target runtime claude_code (matches our default).

2. plugins override on Research Lead + its 3 children + UIUX Designer:
   [ecc, molecule-dev, superpowers, browser-automation]
   - Research agents need live web access for scraping/trending/docs,
     which is core to their role.
   - UIUX Designer gets Puppeteer via CDP; this may work around the
     libglib/X11 gap that breaks Playwright today (#23 — the image-level
     fix remains the right long-term solution, but browser-automation
     uses puppeteer-core + a Chrome CDP proxy and may bypass the deps
     issue entirely).

Note: platform/internal/handlers/org.go:345 treats per-workspace
`plugins:` as a REPLACEMENT of defaults (not a union), which is why
each opt-in workspace re-lists the full set. Documented inline in the
template so future editors don't accidentally drop defaults.

No other roles take browser-automation — Dev Lead, BE, FE, DevOps,
Security, QA, PM all get the default set only. If they need web access
they can install ad-hoc via the runtime plugin API.

org-templates/molecule-dev/org.yaml

@@ -7,6 +7,19 @@ defaults:
   tier: 2
   required_env:
     - CLAUDE_CODE_OAUTH_TOKEN
+  # Default plugin set applied to every workspace unless the workspace
+  # specifies its own `plugins:` list (which REPLACES defaults — not a union;
+  # see platform/internal/handlers/org.go ~L345). So any workspace that
+  # needs extras must re-list the defaults plus its additions.
+  #
+  # - ecc:           "Everything Claude Code" guardrails + coding skills
+  #                  (api-design, coding-standards, deep-research, security-review, tdd-workflow)
+  # - molecule-dev:  Molecule AI codebase conventions, past bugs, review-loop
+  # - superpowers:   systematic-debugging, TDD, planning, verification-before-completion
+  plugins:
+    - ecc
+    - molecule-dev
+    - superpowers
   # workspace_dir: not set by default — each agent gets an isolated Docker volume
   # Set per-workspace to bind-mount a host directory as /workspace
 
@@ -59,6 +72,10 @@ workspaces:
         role: Market analysis and technical research
         files_dir: research-lead
         canvas: { x: 200, y: 250 }
+        # Research roles extend defaults with browser-automation so they can
+        # scrape the live web (product pages, GitHub trending, docs).
+        # Per-workspace plugins REPLACE defaults, so re-list the full set.
+        plugins: [ecc, molecule-dev, superpowers, browser-automation]
         initial_prompt: |
           You just started as Research Lead. Set up silently — do NOT contact other agents.
           1. Clone the repo: git clone https://github.com/${GITHUB_REPO}.git /workspace/repo 2>/dev/null || (cd /workspace/repo && git pull)
@@ -71,12 +88,15 @@ workspaces:
           - name: Market Analyst
             role: Market sizing, trends, user research
             files_dir: market-analyst
+            plugins: [ecc, molecule-dev, superpowers, browser-automation]
           - name: Technical Researcher
             role: AI frameworks and protocol evaluation
             files_dir: technical-researcher
+            plugins: [ecc, molecule-dev, superpowers, browser-automation]
           - name: Competitive Intelligence
             role: Competitor tracking and feature comparison
             files_dir: competitive-intelligence
+            plugins: [ecc, molecule-dev, superpowers, browser-automation]
 
       - name: Dev Lead
         role: Engineering planning and team coordination
@@ -269,6 +289,10 @@ workspaces:
             tier: 3
             model: opus
             files_dir: uiux-designer
+            # Add browser-automation for live canvas screenshots via Puppeteer
+            # (Chrome CDP path, works around the Playwright / libglib gap tracked in #23).
+            # Per-workspace plugins REPLACE defaults — re-list the full set.
+            plugins: [ecc, molecule-dev, superpowers, browser-automation]
             initial_prompt: |
               You just started as UIUX Designer. Set up silently — do NOT contact other agents.
               1. Clone the repo: git clone https://github.com/${GITHUB_REPO}.git /workspace/repo 2>/dev/null || (cd /workspace/repo && git pull)