perf(cli): cut hermes startup 63% — flip head-to-head vs codex (#31968)

* perf(bitwarden): persist secret-fetch cache across CLI invocations

Every `hermes` invocation paid a ~380ms tax for `bws secret list` to
Bitwarden Secrets Manager because the existing cache was in-process only.
Back-to-back `hermes chat -q`, gateway-spawned agents, and cron-launched
runs all re-fetched.

Adds a disk-persisted L2 cache at `<hermes_home>/cache/bws_cache.json`
(mode 0600, never contains the access token — only the SHA-256
fingerprint prefix). Same TTL as the in-process cache. Read on miss,
write on bws success, ignored on key mismatch / corruption / expiry.

Measured on a startup profile:
  load_hermes_dotenv() cold: 372ms → warm (disk cache hit): 20ms

End-to-end `hermes --version` cold→warm: 666ms → ~295ms.

In a hermes-vs-codex benchmark across 11 single- and multi-turn tasks
(framework overhead = wall − llm − tool_exec, median over 3 trials):

  cohort               before    after    saved
  single-turn (median)  2.96s    2.31s   -0.65s
  multi-turn  (5-turn)  9.40s    8.95s   -0.45s (≈0.3s/turn)

Hermes now wins head-to-head on 6/11 tasks vs codex (was 4/11 before).
The remaining ~0.6s single-turn delta is mostly Python's own import
cost in hermes_cli.main, which is a separate optimization.

* perf(cli): lazy-load model catalog + dedupe config.yaml reads at startup

Two import-time wins on top of the bws disk-cache fix:

1. Lazy-load `hermes_cli.models._PROVIDER_MODELS` via PEP 562
   module-level `__getattr__`. The catalog is ~55ms of work that was
   eagerly imported on every CLI invocation (line 4557 `if not
   _is_termux_startup_environment(): from hermes_cli.models import
   _PROVIDER_MODELS`). Audit showed every internal call site already
   does its own function-local import; only test code reads
   `hermes_cli.main._PROVIDER_MODELS` as a module attribute, and
   __getattr__ keeps that working transparently. First access triggers
   the import once and caches the result on the module via
   `globals()[name] = ...`, so subsequent reads are dict lookups.

2. Dedupe the double config.yaml read in the top-of-module bootstrap.
   Previously: one raw yaml.safe_load for the `security.redact_secrets`
   bridge, then a separate full `load_config()` (with deep-merge) for
   `network.force_ipv4`. Both keys come from the same file. Merged
   into one raw yaml load.

Combined with the bws cache fix in the previous commit:

  hermes --version wall time:
    original (cold):           666 ms
    after bws fix (warm):      295 ms
    after lazy-load + dedupe:  228 ms   (-67 ms additional, -66% from original)

Tests:
  - tests/hermes_cli/test_api_key_providers.py: 173/173 pass
    (lazy __getattr__ correctly handles
     `from hermes_cli.main import _PROVIDER_MODELS`)
  - tests/test_ipv4_preference.py + tests/hermes_cli/test_redact_config_bridge.py +
    tests/agent/test_redact.py: 93/93 pass (dedupe preserves both bridges)
  - tests/test_bitwarden_secrets.py + env_loader tests: 49/49 pass

hermes_cli/env_loader.py

@@ -255,6 +255,7 @@ def _apply_external_secret_sources(home_path: Path) -> None:
         cache_ttl_seconds=float(bw_cfg.get("cache_ttl_seconds", 300)),
         auto_install=bool(bw_cfg.get("auto_install", True)),
         server_url=str(bw_cfg.get("server_url", "") or "").strip(),
+        home_path=home_path,
     )
 
     if result.applied: