refactor(prompt-builder): extract API docs into markdown sections

- Split 366-line api-section.ts into 11 category markdown files under
  src/main/prompt-builder/api-docs/ (header, agent-control, tasks,
  goals-projects, approvals, messages, files, knowledge, meetings,
  agents, sprints)
- api-section.ts reduced to ~45 lines: imports each section via ?raw,
  substitutes {{apiUrl}}/{{companyId}}/{{agentId}}/{{runId}}/{{connectorIds}},
  joins sections and appends social media addendum
- Every endpoint signature, body schema, and curl example preserved
  verbatim so LLM instruction surface is unchanged

src/main/prompt-builder/api-docs/knowledge.md

@@ -0,0 +1,13 @@
+### Add Knowledge Entry (lessons learned, best practices)
+POST /api/companies/{{companyId}}/knowledge
+Body: {
+  "category": "lesson_learned|best_practice|decision|process|technical|business|onboarding|incident",
+  "topic": "What we learned",
+  "content": "Detailed description of the knowledge",
+  "importance": "high|medium|low",
+  "referencedEntityType": "task|project|goal",
+  "referencedEntityId": "{optionalEntityId}"
+}
+
+### List Knowledge Base
+GET /api/companies/{{companyId}}/knowledge