Initial StartOS package for Station Master (v0.5.1)

Built from source via a git submodule pinned to a tag, not a published image
— the Dockerfile, main.ts, and manifest should never need to change for an
ordinary version bump, only the submodule pin (see UPDATING.md). One volume,
one interface serving the browser client + lobby/intent API + SSE stream
from a single origin, no dependencies. The server-wide join secret (D14) is
seeded on install, exposed via the Get Join Secret action, and blocks start
behind a critical task until retrieved — the same first-set/rotation pattern
as actual-budget-startos's admin password.

Verified on phoenix.local: installs, the critical task correctly blocks an
ordinary start, force-starting confirms the daemon binds its port and serves
the client, and store.json correctly holds the install-seeded join secret.
Not verified: the Get Join Secret action's execution end-to-end — start-cli's
`package action run` fails with a client-side deserialization error that
reproduces identically against actual-budget's already-shipped equivalent
action, so this looks like a start-cli issue rather than a defect here.

icon.svg is still the scaffold's hello-world placeholder — no real Station
Master icon exists yet to ship in its place.

startos/actions/getJoinSecret.ts

@@ -0,0 +1,51 @@
+import { utils } from '@start9labs/start-sdk'
+import { i18n } from '../i18n'
+import { sdk } from '../sdk'
+import { storeJson } from '../fileModels/store.json'
+
+/**
+ * Mints a fresh join secret on every run and returns it — first-set and rotation are the same
+ * action (recipe-admin-credentials.md). Writing a new value restarts the daemon with it: main.ts
+ * reads `joinSecret` reactively via `.const(effects)`, so a rotation here takes effect
+ * immediately rather than needing a manual restart.
+ *
+ * Rotating invalidates the old secret for anyone who hasn't joined yet, but never removes a
+ * player already seated in a game — D14's secret gates the lobby door only (join-secret ≠
+ * session token, per `lobby-and-sessions.md` §1).
+ */
+export const getJoinSecret = sdk.Action.withoutInput(
+  'get-join-secret',
+
+  async () => ({
+    name: i18n('Get Join Secret'),
+    description: i18n('Retrieve or rotate the secret players need to create or join a game'),
+    warning: null,
+    allowedStatuses: 'any',
+    group: null,
+    visibility: 'enabled',
+  }),
+
+  async ({ effects }) => {
+    const joinSecret = utils.getDefaultString({ charset: 'a-z,A-Z,0-9', len: 24 })
+    await storeJson.merge(effects, { joinSecret })
+
+    return {
+      version: '1',
+      title: 'Join Secret',
+      message:
+        'Share this with anyone you want to be able to create or join a game on this server — ' +
+        "it doesn't identify a person or a seat, just who's allowed at the lobby door. Running " +
+        'this action again generates a new one and restarts the server with it; anyone already ' +
+        'seated in a game keeps playing, but the old secret stops working for new games and joins.',
+      result: {
+        type: 'single',
+        name: 'Join Secret',
+        description: null,
+        value: joinSecret,
+        masked: true,
+        copyable: true,
+        qr: false,
+      },
+    }
+  },
+)

startos/actions/index.ts

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+import { sdk } from '../sdk'
+import { getJoinSecret } from './getJoinSecret'
+
+export const actions = sdk.Actions.of().addAction(getJoinSecret)