Add git domain to explanation grounder

---
Build: pass | Tests: pass — 40 passed (3 files)

---
Build: pass | Tests: pass — 2191 passed (648 files)

src/explanation-grounder.test.ts

@@ -1,6 +1,12 @@
 import { describe, expect, it } from 'vitest';
 
-import { DB_RUNTIME, SUBNET_BASE } from './config.js';
+import {
+  CODE_HOSTING_MODE,
+  DB_RUNTIME,
+  GIT_JAIL_NAME,
+  GIT_LOCAL_URL,
+  SUBNET_BASE,
+} from './config.js';
 import {
   buildExplanationGrounding,
   detectExplanationDomains,
@@ -19,10 +25,16 @@ describe('detectExplanationDomains', () => {
     expect(
       detectExplanationDomains('explain the db jail layout in this project'),
     ).toEqual(['jails']);
+    expect(
+      detectExplanationDomains('how does git work in this project'),
+    ).toEqual(['git']);
+    expect(
+      detectExplanationDomains('explain the Forgejo setup here'),
+    ).toEqual(['git']);
   });
 
   it('falls through when no explanation domain matches yet', () => {
-    expect(detectExplanationDomains('how does git work')).toEqual([]);
+    expect(detectExplanationDomains('restart nginx')).toEqual([]);
   });
 });
 
@@ -47,8 +59,32 @@ describe('buildExplanationGrounding', () => {
     expect(context).toContain('controlplane runs on the host as part of the main service');
   });
 
+  it('builds a git grounding pack from runtime facts and canonical sources', async () => {
+    const context = await buildExplanationGrounding(
+      'how does git work in this project',
+    );
+
+    expect(context).toContain('Domain: git');
+    expect(context).toContain(`CODE_HOSTING_MODE=${CODE_HOSTING_MODE}`);
+    expect(context).toContain(`git jail name: ${GIT_JAIL_NAME}`);
+    expect(context).toContain(`configured local git URL: ${GIT_LOCAL_URL}`);
+    expect(context).toContain('Prefer Forgejo over older Gitea wording');
+    expect(context).toContain(
+      'Do not say this install is in gitea/Forgejo mode unless CODE_HOSTING_MODE explicitly says so',
+    );
+    expect(context).toContain(
+      'Treat GIT_LOCAL_URL as the configured local workflow URL, not proof that this checkout already has that remote added.',
+    );
+    expect(context).toContain('setup/git.ts');
+    expect(context).toContain('docs/public/operate/git-storage.md');
+    expect(context).toContain(
+      'docs/public/architecture/freebsd-jail-implementation.md',
+    );
+    expect(context).toContain('Git Service today uses Forgejo as the shared git web/API implementation');
+  });
+
   it('returns empty when no registered explanation domain matches', async () => {
-    await expect(buildExplanationGrounding('how does git work')).resolves.toBe(
+    await expect(buildExplanationGrounding('restart nginx')).resolves.toBe(
       '',
     );
   });

src/explanation-grounder.ts

@@ -2,7 +2,23 @@ import fs from 'fs';
 import path from 'path';
 import { fileURLToPath } from 'url';
 
-import { DB_RUNTIME, RUNTIME_ID, SUBNET_BASE } from './config.js';
+import {
+  CODE_HOSTING_MODE,
+  CODE_SERVICE_INTERNAL_DOMAIN,
+  DB_RUNTIME,
+  FEATURE_GIT,
+  FEATURE_GITEA,
+  FORGEJO_DB_NAME,
+  GIT_DEFAULT_REPO_NAME,
+  GIT_JAIL_IP,
+  GIT_JAIL_NAME,
+  GIT_LOCAL_URL,
+  GIT_MIRROR_URLS,
+  GIT_STORAGE_ROOT,
+  REMOTE_GIT_URL,
+  RUNTIME_ID,
+  SUBNET_BASE,
+} from './config.js';
 import { getJailIp, getJailRegistry } from './jail-registry.js';
 import { SERVICE_NAME } from './platform-identity.js';
 import { isExplanationPrompt } from './report-intent.js';
@@ -99,6 +115,65 @@ const EXPLANATION_DOMAINS = {
       },
     ],
   },
+  git: {
+    aliases: [
+      /\bgit\b/i,
+      /\bforgejo\b/i,
+      /\bcode\s+service\b/i,
+      /\brepo\b/i,
+      /\brepos\b/i,
+      /\bmirror\b/i,
+      /\bmirrors\b/i,
+      /\bremote\b/i,
+    ],
+    buildRuntimeFacts: () => [
+      `- CODE_HOSTING_MODE=${CODE_HOSTING_MODE}`,
+      `- FEATURE_GIT=${FEATURE_GIT ? 'YES' : 'NO'}`,
+      `- FEATURE_GITEA=${FEATURE_GITEA ? 'YES' : 'NO'}`,
+      `- DB_RUNTIME=${DB_RUNTIME}`,
+      `- git jail name: ${GIT_JAIL_NAME}`,
+      `- git jail IP: ${GIT_JAIL_IP}`,
+      `- git hostname: ${CODE_SERVICE_INTERNAL_DOMAIN}`,
+      `- repo root inside jail: ${GIT_STORAGE_ROOT}`,
+      `- default repo name: ${GIT_DEFAULT_REPO_NAME}`,
+      `- primary upstream remote: ${REMOTE_GIT_URL}`,
+      `- configured local git URL: ${GIT_LOCAL_URL || '(unset)'}`,
+      `- extra mirror remotes: ${GIT_MIRROR_URLS.length > 0 ? GIT_MIRROR_URLS.join(', ') : '(none)'}`,
+      `- Forgejo database name: ${FORGEJO_DB_NAME}`,
+      '- Git Service is a shared platform service; root installs use system_git unless explicitly overridden',
+    ],
+    instructions: [
+      'Prefer Forgejo over older Gitea wording when describing the current shared git web/API implementation.',
+      'Distinguish plain git storage in the git jail from the optional Forgejo application layer.',
+      'Do not say this install is in gitea/Forgejo mode unless CODE_HOSTING_MODE explicitly says so; FEATURE_GITEA=YES only means the optional Forgejo layer is enabled in config.',
+      'Treat GIT_LOCAL_URL as the configured local workflow URL, not proof that this checkout already has that remote added.',
+      'If DB_RUNTIME=host, say Forgejo would use host PostgreSQL rather than implying a separate db jail or Data Service is live.',
+    ],
+    sources: [
+      {
+        label: 'setup/git.ts',
+        loader: () =>
+          extractMarkdownSection(
+            'setup/git.ts',
+            '/**',
+            'function repoNameFromRemote',
+          ),
+      },
+      {
+        label: 'docs/public/operate/git-storage.md',
+        loader: () => readRepoFile('docs/public/operate/git-storage.md'),
+      },
+      {
+        label: 'docs/public/architecture/freebsd-jail-implementation.md',
+        loader: () =>
+          extractMarkdownSection(
+            'docs/public/architecture/freebsd-jail-implementation.md',
+            '### `git`',
+            '### `cms`',
+          ),
+      },
+    ],
+  },
 } satisfies Record<string, ExplanationDomainSpec>;
 
 type ExplanationDomainKey = keyof typeof EXPLANATION_DOMAINS;