feat(secrets): add provider-neutral credential hooks

README.md

@@ -289,6 +289,53 @@ output_dir: results/my_run
 obliteratus run my_study.yaml
 ```
 
+## Credentials and optional vault integration
+
+Environment variables remain the default for quick local development and tests:
+
+```bash
+export HF_TOKEN=hf_example
+export HF_PUSH_TOKEN=hf_example
+export OPENROUTER_API_KEY=sk-or-v1-example
+```
+
+OBLITERATUS also provides a provider-neutral secret hook for deployments backed by
+OpenBao, HashiCorp Vault, Kubernetes, Docker, systemd credentials, or another secret
+manager. No vault SDK is required. Each existing credential name resolves in this
+order:
+
+1. explicit UI or Python argument, where supported;
+2. its existing environment variable;
+3. `<NAME>_FILE`, such as `OPENROUTER_API_KEY_FILE`;
+4. a file in `OBLITERATUS_SECRET_DIR`;
+5. a systemd credential in `CREDENTIALS_DIRECTORY`;
+6. the trusted executable configured by `OBLITERATUS_SECRET_COMMAND`.
+
+Mounted directories use normalized lowercase filenames. For example,
+`OPENROUTER_API_KEY` maps to `openrouter-api-key`, and `HF_TOKEN` maps to
+`hf-token`. Existing uppercase filenames are also accepted. A Vault/OpenBao Agent
+can render those files into a private tmpfs mount:
+
+```bash
+export OBLITERATUS_SECRET_DIR=/run/secrets/obliteratus
+obliteratus ui
+```
+
+For brokers that fetch values on demand, configure one absolute executable path:
+
+```bash
+export OBLITERATUS_SECRET_COMMAND=/usr/local/libexec/obliteratus-secret
+obliteratus ui
+```
+
+The executable receives exactly one argument—the normalized environment-variable
+name—and writes only the secret value to stdout. Exit `0` returns a value, exit `2`
+means the credential is unavailable, and other statuses fail closed. It runs without
+a shell and with a bounded timeout. Treat the executable as privileged deployment
+configuration; never point it at contributor-controlled code or emit diagnostics on
+stdout. Secrets are resolved at use time so mounted-file and broker rotations do not
+require restarting the application.
+
 ## Two intervention paradigms
 
 OBLITERATUS supports both permanent and reversible liberation: