feat(context): direct O&M messages + episodic history for notify judgment and staff/customer chat

[1vav]

Summary

• Grid-analysis chat only reached O&M Telegram chat via an on-demand, staff-only tool the model had to think to call — a real conversation showed alarm data surfacing first and the O&M-reported root cause only after being asked to check for it. Notify's alert-judgment prompt already direct-fetched O&M messages but had no episodic distillation at all, and it's a single-shot LLM call with no tool access, so a tool-based fix was never an option there.
• New chat_orchestrator/orchestrator/services/grid_context_feeds.py, shared by both flows: O&M messages (staff-only, matching customer_get_grid_chat_chronology's own visible_to_customer=False) and episodic distillation (safe for customer scope too — reuses EpisodicProvider's own access gate) are now fetched directly and bounded by count/char caps, bypassing the knowledge-module system's shared token budget, which isn't wired into the notify flow at all.
• O&M per-message truncation moves from 500 to 1000 chars in both flows (free-text field reports read worse cut off at 500 than bot-rendered prior-alert content, which keeps the original 500 cap).
• providers_episodic.py gets reusable resolve_episodic_anchor/fetch_distillation_summary/fetch_episodic_summary functions so neither new call site needs a KnowledgeModule just to reach the same distillation EpisodicProvider already serves — EpisodicProvider.resolve() itself now delegates to fetch_episodic_summary, same behavior, less duplication.
• Short prompt-text additions in staff.system, customer.system, and ticketing.correlation explaining the new context blocks. Note: staff.system and customer.system are live-served from a Google Doc / DB override respectively in production — these bundled-file edits are the fallback copy, not what's live. The live doc/DB versions need a separate update after this merges (tracked outside this PR).

Test plan

• pytest — full chat_orchestrator suite (2539 passed; 1 pre-existing unrelated failure confirmed present on main too)
• pytest shared/tests/ (921 passed; 1 pre-existing unrelated failure confirmed present on main too, caused by stale local .worktrees/ dirs)
• New tests: test_grid_context_feeds.py, test_prepare_context_grid_feeds.py, plus additions to test_alert_judgment_context.py, test_correlator.py, test_notify_alert_delivery_repository.py, test_providers_episodic.py
• prompt_checksums.json regenerated and diff reviewed — only the three touched prompts changed
• ruff check clean
• pre-commit run --all-files clean (test-wiring, loguru guard, operator-data scrub all pass)

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