fix: decouple transient-thinking retry budget from outer max_retries

Greptile caught a real logic bug in the initial patch: the `continue`
inside the transient-thinking branch advanced the outer
`for attempt in range(max_retries + 1)` counter, so each transient retry
consumed a generic-retry slot. With the default `max_retries=5`:

- Loop runs 6 iterations (attempts 0–5)
- Each transient retry burned one iteration
- On attempt 5, `attempt >= max_retries` fired `_raise_error` before the
  6th sleep (160s) ever ran
- The documented "fall through to generic retry" path was unreachable

Fix: inner `while` loop that does its own `_stream()` retry without
advancing the outer `attempt` counter. The transient budget of 6 (5 / 10
/ 20 / 40 / 80 / 160 s) is now independent of `max_retries`, and once
the inner budget is exhausted the most recent exception falls through
to the generic retry path as the PR originally intended.

Also extracts the literal `6` into `max_transient_thinking_retries` for
readability — still unconfigurable since the envelope budget is based on
observed Bedrock transient durations, not something we want users tuning
blindly.

strix/llm/llm.py

@@ -160,6 +160,7 @@ class LLM:
         max_retries = int(Config.get("strix_llm_max_retries") or "5")
 
         transient_thinking_retries = 0
+        max_transient_thinking_retries = 6
 
         for attempt in range(max_retries + 1):
             try:
@@ -171,14 +172,23 @@ class LLM:
                 # blocks have been modified — even when the payload is structurally
                 # valid and the same payload succeeds on replay. Observed on
                 # claude-sonnet-4-6 with adaptive thinking. Retry with exponential
-                # backoff (5s, 10s, 20s, 40s, 80s, 160s — ~5 min total budget) before
-                # falling through to the generic retry path.
-                if self._is_transient_thinking_error(e) and transient_thinking_retries < 6:
+                # backoff (5s, 10s, 20s, 40s, 80s, 160s — ~5 min total budget), using
+                # an inner loop so the transient retry counter does not share slots
+                # with the outer max_retries budget. Once the inner budget is
+                # exhausted (or a non-transient error is raised), fall through to the
+                # generic retry path below.
+                while (
+                    self._is_transient_thinking_error(e)
+                    and transient_thinking_retries < max_transient_thinking_retries
+                ):
                     transient_thinking_retries += 1
-                    if attempt >= max_retries:
-                        self._raise_error(e)
                     await asyncio.sleep(min(240, 5 * (2 ** (transient_thinking_retries - 1))))
-                    continue
+                    try:
+                        async for response in self._stream(messages):
+                            yield response
+                        return  # noqa: TRY300
+                    except Exception as e2:  # noqa: BLE001
+                        e = e2
                 if attempt >= max_retries or not self._should_retry(e):
                     self._raise_error(e)
                 wait = min(90, 2 * (2**attempt))