Docs: six CLI flags missing from the reference table

### What happened?

Six flags registered in `packages/cli/src/config/config.ts` are missing from the flags table in `docs/cli/cli-reference.md`. None of them are hidden — the file marks `fake-responses`, `fake-responses-non-strict` and `record-responses` with `hidden: true`, and these six aren't among them, so they appear in `gemini --help` but not in the docs.

| Flag | Type | Description in source |
| --- | --- | --- |
| `--policy` | array | Additional policy files or directories to load |
| `--admin-policy` | array | Additional admin policy files or directories to load |
| `--session-id` | string | Start a new session with a manually provided UUID |
| `--session-file` | string | Load a session from a JSON file |
| `--raw-output` | boolean | Disable sanitization of model output (e.g. allow ANSI escape sequences) |
| `--accept-raw-output-risk` | boolean | Suppress the security warning when using `--raw-output` |

`--raw-output` is the one I'd flag as most worth documenting. Its own description in the source carries a warning — "WARNING: This can be a security risk if the model output is untrusted" — and `--accept-raw-output-risk` exists purely to silence that warning. A pair of flags where one disables output sanitization and the other suppresses the warning about doing so seems like something the reference should describe, rather than being discoverable only via `--help`.

`--policy` and `--admin-policy` are also relevant given the table already points at the Policy Engine from the `--allowed-tools` row, but never mentions the flags that load policy files.

### What did you expect to happen?

The flags table should list every non-hidden option registered in `config.ts`, so `gemini --help` and the CLI reference agree.

### Client information

Found by comparing the docs against the source rather than at runtime, so not version-specific: it's a gap between `docs/cli/cli-reference.md` and `packages/cli/src/config/config.ts` on current `main` (package version `0.56.0-nightly.20260806.g761f604c1`).

Reproducible without running the CLI: extract the `.option('', {...})` registrations from `config.ts`, drop the three marked `hidden: true`, and diff against the flags in the reference table.

Compare the option registrations in packages/cli/src/config/config.ts with the table in docs/cli/cli-reference.md, excluding the three options marked hidden. Add entries for --policy, --admin-policy, --session-id, --session-file, --raw-output, and --accept-raw-output-risk, preserving their types and source descriptions. Done means every non-hidden option in config.ts is represented in the reference table and the security warning is documented.

Written by the indexing model from the issue text.