fix(direct-assist): fall back to plain text when a skill-prefix guess doesn't resolve

resolveDirectAssistSkill treated any leading "/word" or "$word" as a
mandatory skill invocation and rejected the whole request with
SKILL_NOT_FOUND when that word wasn't a real skill id -- so ordinary
text like "$50 is that a fair price for this laptop?" or "/explain this
regex" broke Direct Assist end-to-end. The renderer's matching prefix
detector (directAssistSkillId) is advisory only; main is authoritative.
Only an explicit UI skill selection (skillId) is unambiguous enough to
hard-fail on a miss -- a bare text-prefix guess that doesn't resolve now
falls back to sending the request as plain text.

Author: Hardening v2.7

electron/ipcHandlers.ts

@@ -6209,6 +6209,15 @@ export function initializeIpcHandlers(appState: AppState): void {
 
     const skill = SkillsManager.getInstance().getSkill(requestedSkillId);
     if (!skill) {
+      // A slash/dollar-prefixed leading word that doesn't resolve to a real
+      // skill is ordinary text far more often than an intended skill
+      // invocation ("$50 is that a fair price...", "/explain this regex") —
+      // the renderer's matching detector (directAssistSkillId) is advisory
+      // only, main is authoritative. Only hard-fail when a skill was
+      // explicitly selected via the UI's skill picker (explicitSkillId),
+      // where there is no ambiguity about intent; a bare text-prefix guess
+      // that misses just falls back to plain text.
+      if (!explicitSkillId) return { currentRequest: request.currentRequest, skill: null };
       return { error: directAssistError('SKILL_NOT_FOUND', 'The requested Direct Assist skill was not found.') };
     }
     if (skill.enabled === false) {

electron/services/__tests__/DirectAssistIpcBridge2026_08_29.test.mjs

@@ -94,6 +94,21 @@ test('main resolves and strips enabled skills, including underscore IDs', () =>
   assert.match(ipc, /instructions: skill\.instructions/);
 });
 
+test('an unresolved text-prefix skill guess falls back to plain text instead of rejecting the request', () => {
+  // A leading "/" or "$" word that doesn't resolve to a real skill is ordinary
+  // text far more often than an intended skill invocation ("$50 is that a
+  // fair price...", "/explain this regex") — only an explicit UI skill
+  // selection (skillId) should hard-fail with SKILL_NOT_FOUND on a miss.
+  const resolveStart = ipc.indexOf('const resolveDirectAssistSkill =');
+  const resolveEnd = ipc.indexOf('\n  safeHandle(', resolveStart);
+  const resolveBlock = ipc.slice(resolveStart, resolveEnd);
+  assert.ok(resolveStart >= 0 && resolveEnd > resolveStart);
+  assert.match(
+    resolveBlock,
+    /if \(!explicitSkillId\) return \{ currentRequest: request\.currentRequest, skill: null \};\s*\n\s*return \{ error: directAssistError\('SKILL_NOT_FOUND'/,
+  );
+});
+
 test('attachments and captured page data are validated before Direct Assist dispatch', () => {
   assert.match(ipc, /const DIRECT_ASSIST_MAX_IMAGES = 5/);
   assert.match(ipc, /candidate\.imagePaths\.length > DIRECT_ASSIST_MAX_IMAGES/);