fix(agent): persist dflash stall retry config

[OmarB97]

Summary

• allow dflash stall retry settings to come from stall_retry config when env vars are absent
• classify repeated empty read-only terminal probes as low-information loops
• add regression coverage for config-backed retry and terminal git diff | grep | head churn

Root Cause

The normal local Hermes CLI did not have HERMES_STALL_RETRY_MODEL in its environment, so the no-tool-call action-preamble retry path was bypassed. The new low-information guardrail also ignored successful terminal probes, so repeated empty shell filters were invisible.

Validation

• python3 -m py_compile agent/stall_retry.py agent/tool_guardrails.py agent/conversation_loop.py agent/agent_init.py
• scripts/run_tests.sh tests/agent/test_stall_retry.py tests/agent/test_tool_guardrails.py tests/run_agent/test_tool_call_guardrail_runtime.py

[github-actions]

🔎 Lint report: fix/terminal-probe-stall-config vs origin/main

ruff

Total: 0 on HEAD, 0 on base (➖ 0)

🆕 New issues: none

✅ Fixed issues: none

Unchanged: 0 pre-existing issues carried over.

ty (type checker)

Total: 9545 on HEAD, 9542 on base (🆕 +3)

🆕 New issues (1):

Rule	Count
invalid-argument-type	1

First entries

agent/stall_retry.py:99: [invalid-argument-type] invalid-argument-type: Argument to constructor `int.__new__` is incorrect: Expected `str | Buffer | SupportsInt | SupportsIndex | SupportsTrunc`, found `Any | None`

✅ Fixed issues: none

Unchanged: 4958 pre-existing issues carried over.

Diagnostics are surfaced as warnings — this check never fails the build.