feat(core): add Discord presence service and extract Jellyfin runtime composition

Introduce Discord presence runtime support and continue composition-root decomposition by moving Jellyfin wiring into dedicated composer modules. This keeps main runtime orchestration thinner while preserving behavior and test coverage across config, runtime, and docs updates.

src/config/resolve/jellyfin.test.ts

@@ -17,7 +17,7 @@ test('jellyfin directPlayContainers are normalized', () => {
 
 test('jellyfin legacy auth keys are ignored by resolver', () => {
   const { context } = createResolveContext({
-    jellyfin: ({ accessToken: 'legacy-token', userId: 'legacy-user' } as unknown) as never,
+    jellyfin: { accessToken: 'legacy-token', userId: 'legacy-user' } as unknown as never,
   });
 
   applyIntegrationConfig(context);
@@ -25,3 +25,61 @@ test('jellyfin legacy auth keys are ignored by resolver', () => {
   assert.equal('accessToken' in (context.resolved.jellyfin as Record<string, unknown>), false);
   assert.equal('userId' in (context.resolved.jellyfin as Record<string, unknown>), false);
 });
+
+test('discordPresence fields are parsed and clamped', () => {
+  const { context } = createResolveContext({
+    discordPresence: {
+      enabled: true,
+      clientId: '123456789',
+      detailsTemplate: 'Watching {title}',
+      stateTemplate: 'Paused',
+      largeImageKey: 'subminer-logo',
+      largeImageText: 'SubMiner Runtime',
+      smallImageKey: 'pause',
+      smallImageText: 'Paused',
+      buttonLabel: 'Open Repo',
+      buttonUrl: 'https://github.com/sudacode/SubMiner',
+      updateIntervalMs: 500,
+      debounceMs: -100,
+    },
+  });
+
+  applyIntegrationConfig(context);
+
+  assert.equal(context.resolved.discordPresence.enabled, true);
+  assert.equal(context.resolved.discordPresence.clientId, '123456789');
+  assert.equal(context.resolved.discordPresence.detailsTemplate, 'Watching {title}');
+  assert.equal(context.resolved.discordPresence.stateTemplate, 'Paused');
+  assert.equal(context.resolved.discordPresence.largeImageKey, 'subminer-logo');
+  assert.equal(context.resolved.discordPresence.largeImageText, 'SubMiner Runtime');
+  assert.equal(context.resolved.discordPresence.smallImageKey, 'pause');
+  assert.equal(context.resolved.discordPresence.smallImageText, 'Paused');
+  assert.equal(context.resolved.discordPresence.buttonLabel, 'Open Repo');
+  assert.equal(context.resolved.discordPresence.buttonUrl, 'https://github.com/sudacode/SubMiner');
+  assert.equal(context.resolved.discordPresence.updateIntervalMs, 1000);
+  assert.equal(context.resolved.discordPresence.debounceMs, 0);
+});
+
+test('discordPresence invalid values warn and keep defaults', () => {
+  const { context, warnings } = createResolveContext({
+    discordPresence: {
+      enabled: 'true' as never,
+      clientId: 123 as never,
+      updateIntervalMs: 'fast' as never,
+      debounceMs: null as never,
+    },
+  });
+
+  applyIntegrationConfig(context);
+
+  assert.equal(context.resolved.discordPresence.enabled, false);
+  assert.equal(context.resolved.discordPresence.clientId, '');
+  assert.equal(context.resolved.discordPresence.updateIntervalMs, 15_000);
+  assert.equal(context.resolved.discordPresence.debounceMs, 750);
+
+  const warnedPaths = warnings.map((warning) => warning.path);
+  assert.ok(warnedPaths.includes('discordPresence.enabled'));
+  assert.ok(warnedPaths.includes('discordPresence.clientId'));
+  assert.ok(warnedPaths.includes('discordPresence.updateIntervalMs'));
+  assert.ok(warnedPaths.includes('discordPresence.debounceMs'));
+});