fix(streaming): prevent <think> in prose from suppressing response output

When the model mentions <think> as literal text in its response (e.g.
"(/think not producing <think> tags)"), the streaming display treated it
as a reasoning block opener and suppressed everything after it. The
response box would close with truncated content and no error — the API
response was complete but the display ate it.

Root cause: _stream_delta() matched <think> anywhere in the text stream
regardless of position. Real reasoning blocks always start at the
beginning of a line; mentions in prose appear mid-sentence.

Fix: track line position across streaming deltas with a
_stream_last_was_newline flag. Only enter reasoning suppression when
the tag appears at a block boundary (start of stream, after a newline,
or after only whitespace on the current line). Add a _flush_stream()
safety net that recovers buffered content if no closing tag is found
by end-of-stream.

Also fixes three related issues discovered during investigation:

- anthropic_adapter: _get_anthropic_max_output() now normalizes dots to
  hyphens so 'claude-opus-4.6' matches the 'claude-opus-4-6' table key
  (was returning 32K instead of 128K)

- run_agent: send explicit max_tokens for Claude models on Nous Portal,
  same as OpenRouter — both proxy to Anthropic's API which requires it.
  Without it the backend defaults to a low limit that truncates responses.

- run_agent: reset truncated_tool_call_retries after successful tool
  execution so a single truncation doesn't poison the entire conversation.

run_agent.py

@@ -5610,20 +5610,20 @@ class AIAgent:
         if self.max_tokens is not None:
             if not self._is_qwen_portal():
                 api_kwargs.update(self._max_tokens_param(self.max_tokens))
-        elif self._is_openrouter_url() and "claude" in (self.model or "").lower():
-            # OpenRouter translates requests to Anthropic's Messages API,
-            # which requires max_tokens as a mandatory field.  When we omit
-            # it, OpenRouter picks a default that can be too low — the model
-            # spends its output budget on thinking and has almost nothing
-            # left for the actual response (especially large tool calls like
-            # write_file).  Sending the model's real output limit ensures
-            # full capacity.  Other providers handle the default fine.
+        elif (self._is_openrouter_url() or "nousresearch" in self._base_url_lower) and "claude" in (self.model or "").lower():
+            # OpenRouter and Nous Portal translate requests to Anthropic's
+            # Messages API, which requires max_tokens as a mandatory field.
+            # When we omit it, the proxy picks a default that can be too
+            # low — the model spends its output budget on thinking and has
+            # almost nothing left for the actual response (especially large
+            # tool calls like write_file).  Sending the model's real output
+            # limit ensures full capacity.
             try:
                 from agent.anthropic_adapter import _get_anthropic_max_output
                 _model_output_limit = _get_anthropic_max_output(self.model)
                 api_kwargs["max_tokens"] = _model_output_limit
             except Exception:
-                pass  # fail open — let OpenRouter pick its default
+                pass  # fail open — let the proxy pick its default
 
         extra_body = {}
 
@@ -9116,6 +9116,11 @@ class AIAgent:
 
                     self._execute_tool_calls(assistant_message, messages, effective_task_id, api_call_count)
 
+                    # Reset per-turn retry counters after successful tool
+                    # execution so a single truncation doesn't poison the
+                    # entire conversation.
+                    truncated_tool_call_retries = 0
+
                     # Signal that a paragraph break is needed before the next
                     # streamed text.  We don't emit it immediately because
                     # multiple consecutive tool iterations would stack up