Feat: improve Signal. Message handling / implement Signal message editing

The api documentation on the Signal Rest api bridge was quite sparse, but it is possible to edit Signal messages via the Rest api bridge

Implementation can be seen here:
https://github.com/Georg311/computer/commit/4a06ec404d2aa6f032ba254729e809d1d2b899dc

With this commit it's possible to send the messages the same in Signal as on other platforms by starting with thinking... And then editing the message to the actual thing.

The fix consists of two changes

cptr/utils/adapters/signal.py — Added edit() method using signal-cli's edit_timestamp field (so messages can be edited in-place instead of sending duplicates)

cptr/utils/bridge.py — Better error logging and early return on edit failures across all platforms

The bridge.py fix was necessary to prevent the message from being duplicated at the end of the message.

I've tried the fix with telegram and Signal, i don't have a discord Account to test there, but it should work as well

Start with cptr/utils/adapters/signal.py and cptr/utils/bridge.py, then inspect the linked implementation commit. Check how Signal's signal-cli edit_timestamp is handled and how bridge edit failures are logged. Done means Signal edits update messages in place without duplicates, with the existing Telegram behavior preserved; Discord remains unverified by the report.