docs(docs): add category index pages and clean up wiki root

Add index.md to: star-systems, corporations, factions, technology,
contraband, concepts. Each lists its contents with brief descriptions.

Rewrite wiki/index.md to link to category indexes instead of inlining
all entries. Regenerate catalog-index.md from DB (remove redundant
System ID column after S-number migration).

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

wiki/technology/index.md

@@ -0,0 +1,14 @@
+# Technology
+
+Core technologies of the Settled Reach.
+
+## Technologies
+
+| Technology | Type | Status |
+|-----------|------|--------|
+| [Neural Lattice](neural-lattice.md) | Brain-computer interface | Universal, tiered |
+| [Meridian](meridian.md) | Information network | Reach-wide |
+| [Founder Gates](founder-gates.md) | Interstellar transit | Alien-built, unmodifiable |
+| [Span Gates](span-gates.md) | Intra-system transit | Human-built (Institute-derived) |
+| [Clone Transfer](clone-transfer.md) | Death/backup system | Body economics |
+| [Severance Tech](severance-tech.md) | Counter-surveillance | Restricted |