Follow-ups on top of the two salvaged GodsBoy commits, all live-validated
against the real Telegram Bot API:
- _edit_overflow_split finalize fallbacks degrade to _strip_mdv2() clean
text instead of putting raw **markdown** markers on screen (salvaged
from PR #43463 minus its format-first sizing — live probes show
Telegram's 4096 limit counts PARSED text, so MarkdownV2 escape
inflation cannot cause MESSAGE_TOO_LONG and sizing against formatted
wire length only causes premature splits and fragment messages).
- Skip the redundant requires-finalize edit after a got_done edit that
split-and-delivered (salvaged from PR #43463): re-finalizing re-splits
the full text into the adopted continuation and duplicates chunks.
- _send_fallback_final only deletes the stale partial message when the
fallback re-sent the COMPLETE final text. When the prefix dedup sent
only the missing tail, the partial IS the head of the answer; deleting
it left users with only the second half of long responses (live-
reproduced: flood-control during a long stream -> head deleted,
ratio 0.54 of content visible). This is the third bug behind the
'Telegram cut messages' reports and was present on main and both PRs.
3b4c715e1c