Add internal-meeting-brief — first real skill in the Brief family

Real-tested 2026-09-21 against the APTA 2026 booth 09-16 planning meeting
(recap mode). Includes:
- skills/internal-meeting-brief/SKILL.md — full workflow: topic resolution,
  continuity manifest, agenda/recap branching, attendee capture/normalization,
  scoped data pulls, synthesis, render, archive.
- assets/brief-components.css — canonical shared component library (cards,
  flow, layerbox/filepill, unitgrid, quad, compare, specbar, actions+status
  pills, note callouts x4 tones, colvis/ring), MPM tokens from CW-028,
  required light/dark toggle, print rules.
- references/section-structure.md — fixed-vs-dynamic section contract,
  explicitly marked unproven beyond one real run.

Known limitation: Plaud MCP connector is currently non-functional (local
server via Claude Desktop, times out). Brief was built from a manually
uploaded transcript, not a live pull.

Five more skills planned, not started: vendor-partner-brief,
status-update-brief, five-whys-brief, kickoff-brief, development-brief.
Full design history in CW-027's Concept.md (Drive).

.claude-plugin/plugin.json

@@ -0,0 +1,9 @@
+{
+  "name": "brief",
+  "version": "0.1.0",
+  "description": "MPM-branded briefing infographics for client/partner, internal, and project meetings. Single-file HTML artifacts, shared component library, agenda/recap modes. First skill shipped: internal-meeting-brief. Five more planned: vendor-partner-brief, status-update-brief, five-whys-brief, kickoff-brief, development-brief.",
+  "author": {
+    "name": "Bryan Gilliom"
+  },
+  "keywords": ["briefing", "meeting", "html", "mpm", "apta"]
+}