fix(telegram): guard rich details math crash

[teknium1]

Summary

Telegram rich messages now fall back to MarkdownV2 for the specific details+math payload shape that can crash Telegram Desktop 6.9.1.

Changes

• gateway/platforms/telegram.py: detect <details>...</details> blocks containing LaTeX-style math and skip sendRichMessage / sendRichMessageDraft for that content.
• tests/gateway/test_telegram_rich_messages.py: cover dangerous details+math send/draft fallback while preserving rich delivery for details without math and math outside details.

Validation

Check	Result
python3 -m py_compile gateway/platforms/telegram.py tests/gateway/test_telegram_rich_messages.py	pass
scripts/run_tests.sh tests/gateway/test_telegram_rich_messages.py	42 passed

Infographic

[github-actions]

🔎 Lint report: fix/telegram-rich-details-math-guard vs origin/main

ruff

Total: 0 on HEAD, 0 on base (➖ 0)

🆕 New issues: none

✅ Fixed issues: none

Unchanged: 0 pre-existing issues carried over.

ty (type checker)

Total: 10906 on HEAD, 10904 on base (🆕 +2)

🆕 New issues (2):

Rule	Count
unresolved-attribute	2

First entries

run_agent.py:2920: [unresolved-attribute] unresolved-attribute: Object of type `Self@get_credits_spent_micros` has no attribute `_credits_session_start_micros`
tests/run_agent/test_credits_notices_toggle.py:76: [unresolved-attribute] unresolved-attribute: Unresolved attribute `_credits_session_start_micros` on type `AIAgent`

✅ Fixed issues (1):

Rule	Count
invalid-assignment	1

First entries

tests/run_agent/test_credits_notices_toggle.py:76: [invalid-assignment] invalid-assignment: Object of type `None` is not assignable to attribute `_credits_session_start_micros` of type `int`

Unchanged: 5735 pre-existing issues carried over.

Diagnostics are surfaced as warnings — this check never fails the build.