fix(agents): add run_in_background to category task() examples in prompts (fixes #3960)

The task() tool schema declares run_in_background as a REQUIRED parameter, but three prompt-template files contained category-based task() examples that omitted it. When agents copied these patterns into actual tool calls, the runtime validator threw 'run_in_background parameter is REQUIRED', breaking delegation.

Add run_in_background=false to the four offending category-based examples: 2 in src/agents/dynamic-agent-category-skills-guide.ts (Delegation Pattern + Category Domain Matching CORRECT/WRONG pair), 1 in src/agents/hephaestus/gpt-5-3-codex.ts (frontend example), and 1 in src/agents/sisyphus/gemini.ts (Example 4 DELEGATE). Subagent-type explore/librarian examples already correctly use run_in_background=true. atlas/shared-prompt.ts examples were already correct.

Verification: bun test src/agents/ — 373 pass, 0 fail. bun run typecheck — clean. Grep confirms no remaining category task() examples lack the parameter.

src/agents/dynamic-agent-category-skills-guide.ts

@@ -102,6 +102,7 @@ Check the \`skill\` tool for available skills and their descriptions. For EVERY
 task(
   category="[selected-category]",
   load_skills=["skill-1", "skill-2"],  // Include ALL relevant skills - ESPECIALLY user-installed ones
+  run_in_background=false,
   prompt="..."
 )
 \`\`\`
@@ -123,10 +124,10 @@ Any task involving UI, UX, CSS, styling, layout, animation, design, or frontend
 
 \`\`\`typescript
 // CORRECT: Visual work → visual-engineering category
-task(category="visual-engineering", load_skills=["frontend-ui-ux"], prompt="Redesign the sidebar layout with new spacing...")
+task(category="visual-engineering", load_skills=["frontend-ui-ux"], run_in_background=false, prompt="Redesign the sidebar layout with new spacing...")
 
 // WRONG: Visual work in wrong category - WILL PRODUCE INFERIOR RESULTS
-task(category="quick", load_skills=[], prompt="Redesign the sidebar layout with new spacing...")
+task(category="quick", load_skills=[], run_in_background=false, prompt="Redesign the sidebar layout with new spacing...")
 \`\`\`
 
 | Task Domain | MUST Use Category |

src/agents/hephaestus/gpt-5-3-codex.ts

@@ -381,6 +381,7 @@ When delegating, ALWAYS check if relevant skills should be loaded:
 task(
   category="visual-engineering",
   load_skills=["frontend-ui-ux"],
+  run_in_background=false,
   prompt="1. TASK: Build the settings page... 2. EXPECTED OUTCOME: ..."
 )
 \`\`\`

src/agents/sisyphus/gemini.ts

@@ -142,7 +142,7 @@ export function buildGeminiToolCallExamples(): string {
 **User**: "Add a new /health endpoint to the API"
 **CORRECT**:
 \`\`\`
-→ Call Task(category="quick", load_skills=["typescript-programmer"], prompt="...")
+→ Call Task(category="quick", load_skills=["typescript-programmer"], run_in_background=false, prompt="...")
 → (After agent completes) Read changed files to verify
 → Call LspDiagnostics on changed files
 → Report