feat: introduce archify skill for generating architecture diagrams

- Added a new Archify skill, enabling users to create polished architecture, workflow, sequence, data-flow, and lifecycle diagrams.
- Implemented comprehensive functionality including rendering, validation, and delivery of diagrams in various formats.
- Integrated a user-friendly command-line interface for generating and previewing diagrams.
- Developed supporting files including package.json, LICENSE, and SKILL.md for documentation and licensing.
- Added unit tests to ensure reliability and functionality of the new skill.

These changes enhance the application by providing a structured approach to visualizing system architecture and workflows, improving user experience and data representation.

.agents/skills/archify/references/brand-marks.md

@@ -0,0 +1,65 @@
+# Brand marks
+
+Use a brand mark only when a real product, provider, model family, channel, or
+service identity helps the reader. Semantic `type` still explains what the node
+does; `brand` explains whose product it is.
+
+## Agent decision path
+
+1. Search the built-in catalogue when the request names a recognizable brand:
+
+   ```bash
+   node bin/archify.mjs brands "Claude" --json
+   ```
+
+2. Put the returned canonical ID in the node, participant, or state:
+
+   ```json
+   {
+     "id": "planner",
+     "type": "backend",
+     "label": "Claude",
+     "brand": "claude"
+   }
+   ```
+
+3. If there is no catalogue match and the user supplied the official website,
+   capture its icon explicitly:
+
+   ```bash
+   node bin/archify.mjs brands capture "https://partner.example.com" --json
+   ```
+
+   Put the command's digest-pinned `brand` value in the authored node:
+
+   ```json
+   {
+     "id": "partner",
+     "type": "external",
+     "label": "Partner portal",
+     "brand": {
+       "url": "https://partner.example.com",
+       "sha256": "0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef"
+     }
+   }
+   ```
+
+4. If there is no match and no user-provided URL, omit `brand`. Do not invent a
+   URL or silently assign a visually similar company.
+
+Known-brand URLs resolve to the bundled vector instead of using the network.
+Unknown URL capture accepts only bounded raster image formats, blocks
+credentials, nonstandard public ports, and private or link-local destinations,
+uses bounded concurrency and one total deadline, and returns the captured
+content digest. Later render and validate operations require that exact digest;
+blocked, unavailable, changed, oversized, or unsafe content fails closed instead
+of silently changing the artifact.
+
+The final artifact never fetches a brand asset when opened. Preset vectors and
+digest-verified captured site icons remain embedded in SVG, PNG, WebP, JPEG,
+Share Card, and WebM exports.
+
+Use `node bin/archify.mjs brands --json` to inspect all canonical IDs, aliases,
+categories, domains, and provenance. Current categories cover AI, cloud,
+engineering, data, collaboration, business systems, channels, languages, and
+frameworks.