fix: Telegram streaming — config bridge, not-modified, flood control (#1782)

* fix: NameError in OpenCode provider setup (prompt_text -> prompt)

The OpenCode Zen and OpenCode Go setup sections used prompt_text()
which is undefined. All other providers correctly use the local
prompt() function defined in setup.py. Fixes crash during
'hermes setup' when selecting either OpenCode provider.

* fix: Telegram streaming — config bridge, not-modified, flood control

Three fixes for gateway streaming:

1. Bridge streaming config from config.yaml into gateway runtime.
   load_gateway_config() now reads the 'streaming' key from config.yaml
   (same pattern as session_reset, stt, etc.), matching the docs.
   Previously only gateway.json was read.

2. Handle 'Message is not modified' in Telegram edit_message().
   This Telegram API error fires when editing with identical content —
   a no-op, not a real failure. Previously it returned success=False
   which made the stream consumer disable streaming entirely.

3. Handle RetryAfter / flood control in Telegram edit_message().
   Fast providers can hit Telegram rate limits during streaming.
   Now waits the requested retry_after duration and retries once,
   instead of treating it as a fatal edit failure.

Also fixed double-edit on stream finish: the consumer now tracks
last-sent text and skips redundant edits, preventing the not-modified
error at the source.

* refactor: make config.yaml the primary gateway config source

Eliminates the per-key bridge pattern in load_gateway_config().
Previously gateway.json was the primary source and each config.yaml
key needed an individual bridge — easy to forget (streaming was
missing, causing garl4546's bug).

Now config.yaml is read first and its keys are mapped directly into
the GatewayConfig.from_dict() schema. gateway.json is kept as a
legacy fallback layer (loaded first, then overwritten by config.yaml
keys). If gateway.json exists, a log message suggests migrating.

Also:
- Removed dead save_gateway_config() (never called anywhere)
- Updated CLI help text and send_message error to reference
  config.yaml instead of gateway.json

---------

Co-authored-by: Test <test@test.com>

gateway/platforms/telegram.py

@@ -414,7 +414,10 @@ class TelegramAdapter(BasePlatformAdapter):
                     text=formatted,
                     parse_mode=ParseMode.MARKDOWN_V2,
                 )
-            except Exception:
+            except Exception as fmt_err:
+                # "Message is not modified" is a no-op, not an error
+                if "not modified" in str(fmt_err).lower():
+                    return SendResult(success=True, message_id=message_id)
                 # Fallback: retry without markdown formatting
                 await self._bot.edit_message_text(
                     chat_id=int(chat_id),
@@ -423,6 +426,32 @@ class TelegramAdapter(BasePlatformAdapter):
                 )
             return SendResult(success=True, message_id=message_id)
         except Exception as e:
+            err_str = str(e).lower()
+            # "Message is not modified" — content identical, treat as success
+            if "not modified" in err_str:
+                return SendResult(success=True, message_id=message_id)
+            # Flood control / RetryAfter — back off and retry once
+            retry_after = getattr(e, "retry_after", None)
+            if retry_after is not None or "retry after" in err_str:
+                wait = retry_after if retry_after else 1.0
+                logger.warning(
+                    "[%s] Telegram flood control, waiting %.1fs",
+                    self.name, wait,
+                )
+                await asyncio.sleep(wait)
+                try:
+                    await self._bot.edit_message_text(
+                        chat_id=int(chat_id),
+                        message_id=int(message_id),
+                        text=content,
+                    )
+                    return SendResult(success=True, message_id=message_id)
+                except Exception as retry_err:
+                    logger.error(
+                        "[%s] Edit retry failed after flood wait: %s",
+                        self.name, retry_err,
+                    )
+                    return SendResult(success=False, error=str(retry_err))
             logger.error(
                 "[%s] Failed to edit Telegram message %s: %s",
                 self.name,