style: UI polish and miscellaneous fixes

Fixes link color from hardcoded white to currentColor for proper theme
support. Adds video and audio modality icons to ModelInfo. Registers
anthropic, nvidia, and xiaomi in the provider icon map. Removes unused
pagination validation from agents and topics endpoints. Adds convenience
start script. Updates AGENTS.md.

start-veridian.sh

@@ -0,0 +1,32 @@
+#!/bin/bash
+
+SESSION_NAME="veridian"
+
+if tmux has-session -t "$SESSION_NAME" 2>/dev/null; then
+    tmux attach-session -t "$SESSION_NAME"
+    exit 0
+fi
+
+tmux new-session -d -s "$SESSION_NAME" -n "dev"
+
+TERMINAL_SIZE=$(stty size 2>/dev/null)
+ROWS=$(echo "$TERMINAL_SIZE" | awk '{print $1}')
+COLS=$(echo "$TERMINAL_SIZE" | awk '{print $2}')
+
+# Divide columns by 2 because nearly all terminal fonts are 8x16, so to 
+# *correctly* maximize the space each pane takes up, we need to divide by 2
+if [ "$ROWS" -gt $(("$COLS" / 2)) ]; then
+    tmux split-window -v -t "$SESSION_NAME"
+else
+    tmux split-window -h -t "$SESSION_NAME"
+fi
+
+tmux set -t "$SESSION_NAME" mouse on
+tmux bind-key -n Pageup copy-mode -u
+
+tmux send-keys -t "$SESSION_NAME:0.0" "frpc -c frpc.toml" C-m
+tmux send-keys -t "$SESSION_NAME:0.1" "bun i && bun dev" C-m
+
+tmux select-pane -t "$SESSION_NAME:0.0"
+
+tmux attach-session -t "$SESSION_NAME"