refactor(llc/frontend): consolidate duplicated tree-build, status-color, and run-status mapping in LLC views #9909

Discovered during

LLC ship (#9861 / PR #9902) — retrospective review of the touched LLC views surfaced copy-paste duplication across autobot-frontend/src/views/llc/.

Duplication (file:line)

1. markExpanded() — identical recursive tree-expander duplicated:
   • GoalTree.vue:76
   • SubCompanyTree.vue:71
2. Build-forest-from-parent — same "group children under parent pointer" logic:
   • GoalTree.vue:31 (buildGoalTree, parent_goal_id)
   • SubCompanyTree.vue (mapNode recursion)
   • (backend mirror: companies.py get_org_chart forest assembly via reports_to — cross-language, can't share, but the FE copies can.)
3. statusColor() — identical status → tailwind bg-* map duplicated 3×:
   • OrgTreeNode.vue:27, CompanyTreeNode.vue:30, CompanyDashboard.vue:149
4. Agent run-status → display-status mapping — LLCRunStatus value translation duplicated:
   • CompanyDashboard.vue:84 (runStatusToAgentStatus) and :108 (mapRun, completed→done)
   • drift risk against the backend's _heartbeat_status_to_org_status (companies.py).
5. Status vocabulary 'active' | 'idle' | 'error' | 'paused' hand-typed in OrgTreeNode.vue:12, CompanyDashboard.vue:28 (should derive from generated API types or a shared const).

Suggested consolidation

• composables/llc/useLlcTree.ts — markExpanded + buildTreeFromParent(items, idKey, parentKey).
• composables/llc/llcStatus.ts — the status union type, statusColor(), and runStatusToDisplayStatus() (single source aligned with LLCRunStatus).

Non-blocking; no behavior change. Filed per "every duplication is an issue".