Per-device tokens with revocation (issue #11)

Auth previously used the shared IRIS_TOKEN as the security principal:
a leaked token meant access to all devices, and a compromised device
could not be isolated.

Gateway:
- pairing.py: devices.token column (in-place migration) + revoked
  denylist table; issue_token (idempotent, 64 hex), token_for,
  reissue_token, revoke/unrevoke/is_revoked/list_revoked. The token
  never leaks into device dicts (push fan-out / listings).
- http_server.py: auth accepts the shared token (bootstrap/legacy) OR
  the device's own token (both constant-time); a revoked device_id is
  rejected with 401 before either comparison. On SSE open (pairing)
  the per-device token is minted and returned in hello.ack.
- protocol.py: hello_ack(..., device_token).
- adapter.py: setup flow (hermes gateway setup -> Iris) now offers
  'Remove a paired device?' on an existing setup: numbered select
  menu (last option = exit the removal loop), confirmation, back to
  the menu for further removals.
- tools/iris_devices.py: operator CLI (list / revoke / unrevoke /
  reissue), stdlib only.

App:
- SecureStore.deviceToken (Android: EncryptedSharedPreferences;
  Desktop: second keyring slot iris-device-token / device_token.enc).
- HelloAckPayload.deviceToken; GatewayClient stores it on hello and
  presents it instead of the shared token from then on (live provider
  in HttpGateway); savePairing/clear wipe it for re-pairing.

Docs: 09 §9.3 stretch -> implemented (revocation semantics, both
control surfaces), 04 hello.ack example, frames.schema.json, M7 row 13.

Tests: 8 new Python tests (issuance, acceptance, revocation,
isolation, unrevoke, registry unit x2, setup-flow menu) - 94/94 pass;
2 new Kotlin wire tests - green. Live-verified against a running
gateway (hello.ack token matches devices.db; revoke -> 401 even with
shared token; unrevoke -> 200; setup TUI both paths).

docs/12-toolchain.md

@@ -9,6 +9,7 @@ First-time setup on a machine (verified baseline: CachyOS/Arch, `pacman`,
 pacman -S jdk17-openjdk
 java -version   # expect 17.x
 ```
+
 (Compose Multiplatform + current AGP are happy on JDK 17. Use 17 to match the
 Android toolchain; 21 also works but 17 is the safe floor.)
 
@@ -28,10 +29,12 @@ export PATH=$PATH:$ANDROID_HOME/cmdline-tools/latest/bin:$ANDROID_HOME/platform-
 sdkmanager --licenses
 sdkmanager "platform-tools" "platforms;android-34" "build-tools;34.0.0"
 ```
+
 Persist `ANDROID_HOME`/`PATH` in `~/.bashrc`. ADB is already installed system-wide;
 `platform-tools` from the SDK is fine too (whichever is first on `PATH`).
 
 Create `app/local.properties`:
+
 ```
 sdk.dir=/home/<you>/android-sdk
 ```
@@ -39,10 +42,12 @@ sdk.dir=/home/<you>/android-sdk
 ## 12.3 Gradle
 
 No system install — use the project wrapper:
+
 ```bash
 cd app
 ./gradlew tasks        # first run downloads the wrapper distribution
 ```
+
 (The wrapper version is pinned in `app/gradle/wrapper/gradle-wrapper.properties`.)
 
 ## 12.4 hermes environment (for the plugin + running the gateway)
@@ -53,7 +58,9 @@ uv sync                # creates .venv with all core deps (websockets, httpx,
 source .venv/bin/activate
 hermes --version       # sanity
 ```
+
 - Run the gateway with the plugin:
+
   ```bash
   # install the plugin (dev: symlink)
   mkdir -p ~/.hermes/plugins
@@ -61,7 +68,9 @@ hermes --version       # sanity
   hermes gateway status     # should list "iris"
   hermes gateway            # run
   ```
+
 - Tests use hermes's hermetic runner (never bare `pytest`):
+
   ```bash
   scripts/run_tests.sh tests/gateway/test_android.py
   ```
@@ -84,6 +93,7 @@ hermes --version       # sanity
 ## 12.6 Environment variables (summary)
 
 **Secrets (`~/.hermes/.env`):**
+
 ```
 IRIS_TOKEN=<64-hex>
 IRIS_PUSH_BACKEND=ntfy           # default; fcm = opt-in (metadata via Google)
@@ -96,6 +106,7 @@ IRIS_FCM_SERVICE_ACCOUNT=/path/to/service-account.json
 ```
 
 **Behavioral (`~/.hermes/config.yaml`):**
+
 ```yaml
 gateway:
   platforms:
@@ -135,5 +146,6 @@ async def main():
 asyncio.run(main())
 PY
 ```
+
 Expect a `hello.ack`. If you get `error {code:"auth"}`, the token/host/port is
-wrong.
+wrong.