* refactor(plugins): remove the Sep 2026 decomposition compat layer on schedule
The PLUGIN-COMPAT layer (2776813df3 + d63e380324 + 0a5164cebe) kept pre-#102117 import paths
alive for external plugins until 2026-09-14. That window closed two weeks ago; since then the loader
has already been skipping plugins that use the old paths. This removes the layer itself:
- 328 appended `PLUGIN-COMPAT` blocks (lazy `__getattr__` pointer tables, re-exported third-party
names, restored dead definitions) and the three re-export stub modules
(gateway/startup_watchdog, hermes_cli/observability/relay_runtime, tools/environments/modal_utils)
- COMPAT_MANIFEST.md, compat_manifest.json, scripts/check_compat_pointers.py and its lint step
- the reporting surfaces: CLI banner notice, `hermes plugins compat`, the `hermes doctor` section,
the post-update notice, the Desktop one-time dialog, the loader's pre-import skip and the
`plugins.allow_deprecated_imports` escape hatch
An external plugin that still imports an old path now fails to load with its ImportError as the
reason in `hermes plugins list`, the same path as any broken plugin.
hermes_cli/plugin_compat.py stays as three inert stubs (compat_report, removal_in_effect,
summary_lines): an already-running pre-removal `hermes update` lazy-imports them after the checkout
swap (tests/compat/old_updater_surface.json).
In-tree fallout, both already dead: hermes_cli/setup.py::_check_espeak_ng (no callers; its
`shutil` came from a compat block) and gateway/config.py::SessionResetPolicy ("retained solely for
the scheduled plugin-compat window"). Two test_run_agent patches targeted the removed
`run_agent.handle_function_call` pointer; they now patch `model_tools.handle_function_call`, the
seam production reads, like every sibling test in that file.
* chore: retrigger CI (zero-job startup_failure phantom)
* test: drop resolution allowlist rows for the two deleted which() sites
hermes_cli/setup.py::_check_espeak_ng (dead) and tools/skillevaluator_scan.py::scanner_available
(a restored definition inside a PLUGIN-COMPAT block) no longer exist; the stale-row gate requires
their allowlist entries go with them.