test(tui): shard tui gateway test suite s4 clusters (tests/test_tui_gateway_server.py, tracker #78647) - #80540

What changed and why

Shard slice for the tests/test_tui_gateway_server.py large-file decomposition (tracker #78647, tracker #78629). This is region s4 of the 5×2×3 double-blind decomposition: the model-switch-deferral and pending-respond test families move verbatim into focused observable modules.

• Moved (5 tests, byte-verbatim):
  • model-switch-deferral family (4 tests) → tests/tui_gateway/test_model_switch_deferral.py
  • pending-respond family (1 test) → tests/tui_gateway/test_pending_respond.py
• Zero behavior change: pure test refactor (test-file godfile — no runtime code touched).

How to test

HERMES_PYTHON="C:/Users/andre/AppData/Local/hermes/hermes-agent/venv/Scripts/python.exe" scripts/run_tests.sh tests/tui_gateway/test_model_switch_deferral.py tests/tui_gateway/test_pending_respond.py
# expected: 5 passed, 0 failed

Footgun Gate

git diff --check is clean on each branch. The newly added modules each scan clean (check-windows-footguns.py: 0 findings). The retained godfile carries 10 pre-existing bare Path.read_text/write_text encoding findings; a pristine pin scan reproduced the same 10 findings. No slice-introduced footgun exists; the retained-godfile baseline debt is outside these extracted test windows and remains staged for a later test-hygiene class fix.

Verification (blind, 5×2×3)

Double-blind witnesses w2a + w2b (independent, forbidden from each other's outputs and from W1 artifacts) both VERIFIED:

• Byte-fidelity: all 5 moved defs AST-slice-identical to pin 9d4ef04ed00 source
• Orphan gate: 0 moved defs remain in the godfile; each exists exactly once in its module
• Seam check: PASS
• Focused suite: 5 passed / 0 failed (both witnesses)
• git diff --check clean; py_compile clean; working tree clean at commit 0fdec7e7df4

Witness verdicts: C:/tmp/tg-campaign/godfile/tui_test/extraction/ew2/s4-w2a.json, s4-w2b.json (schema tui-test-extraction-w2-witness/1.0, both VERIFIED).

Platforms tested

Windows (git-bash host), repo main venv python 3.11.

Why this matters to users

No user-visible change — large-file decomposition: the 16,245-line test monolith shrinks, each focused module is independently runnable and debuggable, and the 2K-law kill track advances. Test-file slices are behavior-neutral by construction (epic method 3).

Part of #78647
Part of #78629

Links

• This PR: test(tui): shard tui gateway test suite s4 clusters (tests/test_tui_gateway_server.py, tracker #78647) #80540
• God-file tracker: Shard tests/test_tui_gateway_server.py (god-file decomposition) #78629
• Kill-All-Gods epic: Repo-wide godfile eradication: residual 2K tasks after #102117 #78647
• KILL LOCK comment: Shard tests/test_tui_gateway_server.py (god-file decomposition) #78629 (comment)
• Scoreboard comment: Shard tests/test_tui_gateway_server.py (god-file decomposition) #78629 (comment)
• Slice PR test(tui): shard tui gateway test suite s1 clusters (tests/test_tui_gateway_server.py, tracker #78647) #80537: test(tui): shard tui gateway test suite s1 clusters (tests/test_tui_gateway_server.py, tracker #78647) #80537
• Slice PR test(tui): shard tui gateway test suite s2 clusters (tests/test_tui_gateway_server.py, tracker #78647) #80538: test(tui): shard tui gateway test suite s2 clusters (tests/test_tui_gateway_server.py, tracker #78647) #80538
• Slice PR test(tui): shard tui gateway test suite s3 clusters (tests/test_tui_gateway_server.py, tracker #78647) #80539: test(tui): shard tui gateway test suite s3 clusters (tests/test_tui_gateway_server.py, tracker #78647) #80539
• Slice PR test(tui): shard tui gateway test suite s4 clusters (tests/test_tui_gateway_server.py, tracker #78647) #80540: test(tui): shard tui gateway test suite s4 clusters (tests/test_tui_gateway_server.py, tracker #78647) #80540
• Slice PR test(tui): shard tui gateway test suite s5 clusters (tests/test_tui_gateway_server.py, tracker #78647) #80541: test(tui): shard tui gateway test suite s5 clusters (tests/test_tui_gateway_server.py, tracker #78647) #80541