fix(kanban): preserve Telegram DM topic notification metadata

[embwl0x]

Summary

• persist per-subscription delivery metadata for Kanban notifications
• carry Telegram DM-topic reply metadata from slash/tool auto-subscribe paths into notifier sends
• add session chat type to the session context bridge so tool-created tasks can distinguish Telegram DMs from group/forum topics

Fixes #60600

Tests

• uv run --extra dev pytest tests/gateway/test_kanban_notifier.py tests/hermes_cli/test_kanban_db_init.py tests/hermes_cli/test_kanban_core_functionality.py::test_notify_sub_crud tests/hermes_cli/test_kanban_notify.py::test_gateway_create_autosubscribes_on_explicit_board tests/tools/test_kanban_tools.py::test_create_subscribes_gateway_session tests/gateway/test_session_env.py -q
• uv run --extra dev pytest tests/gateway/test_telegram_thread_fallback.py::test_base_gateway_metadata_marks_telegram_dm_topics_as_reply_fallback tests/gateway/test_delivery.py::test_explicit_telegram_private_thread_uses_reply_fallback_with_anchor -q
• uv run --extra dev pytest tests/gateway/test_kanban_notifier.py tests/hermes_cli/test_kanban_notify.py tests/tools/test_kanban_tools.py -q
• uv run --extra dev pytest tests/gateway/test_session_context_inheritance.py tests/gateway/test_session_env.py tests/tools/test_local_env_session_leak.py -q
• git diff --check
• gitleaks git --log-opts='origin/main..HEAD' --redact .

[embwl0x]

Final overlap audit: #56632/#58615 persist chat_type so synthetic Kanban wakes land in the right DM/group session. This PR addresses the separate #60600 delivery failure: it persists and reuses the Telegram DM-topic reply anchor and fallback metadata required by the adapter safety guard, covering both slash-command and tool auto-subscribe paths. The prior PRs do not carry those send-time fields.

[teknium1]

Thanks for addressing the DM-topic delivery path. The premise is confirmed on current main: gateway/kanban_watchers.py:408-418 forwards only thread_id, while gateway/delivery.py:517-524 rejects a private-topic delivery without a reply anchor. The persisted replay metadata in this PR directly addresses that contract for both subscription writers.

Problems

• The new HERMES_SESSION_CHAT_TYPE bridge lacks a direct regression assertion. tests/gateway/test_session_env.py:33-72 builds a SessionSource(chat_type="group") and calls _set_session_env(), but does not verify HERMES_SESSION_CHAT_TYPE; the tool-created subscription path now depends on it.

Suggested changes

• Add set-and-clear assertions for get_session_env("HERMES_SESSION_CHAT_TYPE") in tests/gateway/test_session_env.py.

GitHub currently reports this PR MERGEABLE/CLEAN; current-main changes since its base do not touch its production files. This is an automated hermes-sweeper review.

[teknium1]

Merged via PR #72232 — both your commits (this one and #63927) were cherry-picked onto current main with your authorship preserved. The delivery_metadata persistence composed cleanly with the chat_type column that landed via #72191. Thanks for root-causing both halves of the DM-topic failure!