docs(decisions): renumber insert icon system D-084 → D-086

Resolves ID collision: D-084 was used independently by both the copy
branch (line ID scheme, content.md) and the visual branch (insert icon
system, perception.md). Content's D-084 keeps the number; visual's is
renumbered to D-086.

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

decisions/perception.md

@@ -446,7 +446,7 @@ How the player observes and interacts with the world: camera, fog, line-of-sight
 - **Implements:** Tickets #547 (struct + detection), #550 (monologue + event chain)
 - **Cross-reference:** [D-034](content.md#d-034-the-friend-npc-archetype), [D-033](perception.md#d-033-entity-color--relationship-to-player), [D-041](architecture.md#d-041-knowledge-graph-data-model), [D-079](#d-079-knowledge-grant-architecture), [D-080](#d-080-npc-to-npc-knowledge-propagation)
 
-### D-084: Insert icon system — custom SVG, no icon font
+### D-086: Insert icon system — custom SVG, no icon font
 - **Date:** 2026-02-24
 - **Decision:** The insert overlay (z-layer 6) uses **custom SVG icons**, not an icon font. The v0.1 icon vocabulary (~12–15 shapes: stance indicators, perception mode icons, inventory item silhouettes, border arrows) is too small and too specific for a font. No available icon font (Material Symbols, Phosphor, Feather, Tabler) matches the insert's geometric/diegetic visual language — they all read as "app UI," not "neural lattice overlay." Custom SVGs authored to the insert's constraint set (clean geometry, minimal anchor points, `#c8d0e0` chrome color, 1px stroke base weight) ensure all insert elements feel generated by the same system.
 - **Why not an icon font:**
@@ -467,4 +467,4 @@ How the player observes and interacts with the world: camera, fog, line-of-sight
 
 ---
 
-*38 decisions. Last updated: 2026-02-24 (D-084: Insert icon system)*
+*38 decisions. Last updated: 2026-02-24 (D-086: Insert icon system)*