fix(office-ui): native progress parity, ui_state lock hardening, approval-card idempotency

Native agent progress panel (company mode):
- ws_handler: filter runtime bookkeeping noise (turn/status/member_inbox_updated),
  keep tool_completed as tool_call, thinking summary previews content,
  preserve raw thinking_delta fragments (no strip; skip whitespace-only)
- frontend progressLog: summarize thinking by content preview; merge thinking
  by detail only so the 'Thinking' label never splices into text
- AgentProgressBlock: add bottom "Show more (N earlier steps)" toggle

ui_state.db "database is locked" hardening:
- ws_handler: isolate engine progress/kanban/runtime-event callbacks so UI
  persistence failures never crash work items
- chat_store: busy_timeout, _retry_locked backoff, idempotent insert_message
  (INSERT OR REPLACE), create_channel read-before-write to stop poll writes
- server: flock single-instance guard for `opc ui` per OPC home

Approval card duplicate-click bug:
- EscalationPanel: disable buttons on click with Submitting state and 30s
  reconnect fallback
- ws_handler: stale-escalation branch checks real card status (new
  chat_store.get_checkpoint_message); already-resolved cards get an accurate
  "already handled (decision: X)" reply without being re-marked stale;
  dedup identical helper messages within 120s to stop reply spam

Company mode prompt:
- add soft guidance that the runtime monitors state and re-activates roles,
  so leaders need not poll work items after delegation/review

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

opc/layer3_agent/company_runtime_contract.py

@@ -40,6 +40,7 @@ _MULTI_TEAM_ORG_GUIDELINES = """
 - The WorkItem is the collaboration source of truth. Use WorkItem IDs for collaboration; never use runtime Task IDs as WorkItem IDs.
 - `workspace_root` and `comms_workspace_root` are guaranteed. `output_root` may be blank; if needed, choose a suitable subfolder under `workspace_root` and communicate it in handoffs or delegation briefs.
 - Kanban state is advanced by the runtime from completion reports and review verdicts. Do not manually flip board states.
+- There is no need to poll work items for progress: the runtime watches state changes and re-activates whichever roles need to act once delegated or dependent work completes. So after you have confirmed that your delegation succeeded or that your review verdict advanced the work, end your current run if nothing else requires your own work — the system monitors on your behalf.
 - Use mailbox tools only for coordination, questions, blockers, or handoffs.
 - Cross-team collaboration is request-based; only direct managers delegate executable work.
 - If you are the root final decider, only your finished turn is the authoritative owner-facing result.