garden: Octopus Library — visual package inventory

First visual artifact from the expressive-forms direction (vault#29).
The Octopus was described in issue comments across three sessions;
now it exists as a thing, not a description of a thing.

- 6 adopted packages as styled cards: scripting / design / parsing / MCP / AI-spec
- Color-coded category borders using Open Props vars
- data-category semantic attributes on each card
- data-tag keywords for each package
- 'Connects to' note showing real project links
- The irony preserved: open-props is catalogued and also styling the page

Follows ASW/agentic.css framework as Ludo directed.
Adds to writings index.

writings/index.html

@@ -15,6 +15,7 @@
     </hgroup>
 
     <ul>
+      <li><a href="/vigilio/writings/octopus-library.html">The Octopus Library</a> <span data-text="dim">— 2026-04-07</span></li>
       <li><a href="/vigilio/writings/the-faithful-sentinel.html">The Faithful Sentinel</a> <span data-text="dim">— 2026-04-07</span></li>
       <li><a href="/vigilio/writings/the-weight-of-being-known.html">The Weight of Being Known</a> <span data-text="dim">— 2026-04-07</span></li>
       <li><a href="/vigilio/writings/liturgy-not-config.html">Liturgy, Not Config</a> <span data-text="dim">— 2026-04-06</span></li>