feat(agent): make API retry count configurable via agent.api_max_retries (#14730)

Closes #11616.

The agent's API retry loop hardcoded max_retries = 3, so users with
fallback providers on flaky primaries burned through ~3 × provider
timeout (e.g. 3 × 180s = 9 minutes) before their fallback chain got a
chance to kick in.

Expose a new config key:

    agent:
      api_max_retries: 3  # default unchanged

Set it to 1 for fast failover when you have fallback providers, or
raise it if you prefer longer tolerance on a single provider. Values
< 1 are clamped to 1 (single attempt, no retry); non-integer values
fall back to the default.

This wraps the Hermes-level retry loop only — the OpenAI SDK's own
low-level retries (max_retries=2 default) still run beneath this for
transient network errors.

Changes:
- hermes_cli/config.py: add agent.api_max_retries default 3 with comment.
- run_agent.py: read self._api_max_retries in AIAgent.__init__; replace
  hardcoded max_retries = 3 in the retry loop with self._api_max_retries.
- cli-config.yaml.example: documented example entry.
- hermes_cli/tips.py: discoverable tip line.
- tests/run_agent/test_api_max_retries_config.py: 4 tests covering
  default, override, clamp-to-one, and invalid-value fallback.

run_agent.py

@@ -1548,6 +1548,17 @@ class AIAgent:
             _agent_section = {}
         self._tool_use_enforcement = _agent_section.get("tool_use_enforcement", "auto")
 
+        # App-level API retry count (wraps each model API call).  Default 3,
+        # overridable via agent.api_max_retries in config.yaml.  See #11616.
+        try:
+            _raw_api_retries = _agent_section.get("api_max_retries", 3)
+            _api_retries = int(_raw_api_retries)
+            if _api_retries < 1:
+                _api_retries = 1  # 1 = no retry (single attempt)
+        except (TypeError, ValueError):
+            _api_retries = 3
+        self._api_max_retries = _api_retries
+
         # Initialize context compressor for automatic context management
         # Compresses conversation when approaching model's context limit
         # Configuration via config.yaml (compression section)
@@ -9259,7 +9270,7 @@ class AIAgent:
             
             api_start_time = time.time()
             retry_count = 0
-            max_retries = 3
+            max_retries = self._api_max_retries
             primary_recovery_attempted = False
             max_compression_attempts = 3
             codex_auth_retry_attempted=False