fix: style agent mentions with primary color in markdown messages

Agent @mentions in markdown use the primary accent instead of generic link color
Mentions render without external URL favicons
Markdown mode now matches plain text mention styling

packages/ui/src/lib/messages/inlineMessageLinks.ts

@@ -0,0 +1,29 @@
+export const SKILL_LINK_PREFIX = '#openchamber-skill:';
+export const AGENT_LINK_PREFIX = '#openchamber-agent:';
+
+export const buildAgentMentionUrl = (name: string): string => {
+    const encoded = encodeURIComponent(name);
+    return `https://opencode.ai/docs/agents/#${encoded}`;
+};
+
+export const buildSkillHref = (name: string): string => `${SKILL_LINK_PREFIX}${encodeURIComponent(name)}`;
+
+export const buildAgentHref = (name: string): string => `${AGENT_LINK_PREFIX}${encodeURIComponent(name)}`;
+
+export const parseSkillHref = (href: string | null | undefined): string | null => {
+    if (!href?.startsWith(SKILL_LINK_PREFIX)) return null;
+    try {
+        return decodeURIComponent(href.slice(SKILL_LINK_PREFIX.length));
+    } catch {
+        return null;
+    }
+};
+
+export const parseAgentHref = (href: string | null | undefined): string | null => {
+    if (!href?.startsWith(AGENT_LINK_PREFIX)) return null;
+    try {
+        return decodeURIComponent(href.slice(AGENT_LINK_PREFIX.length));
+    } catch {
+        return null;
+    }
+};