feat: add admin publishing workflow and yar theme

Add Go/Postgres admin APIs, Angular admin UI, manual build flow, asset uploads, markdown import/export, configurable slug generation, and the Yar reading theme. Exclude local docs and generated development artifacts from version control.

frontend/admin/src/app/admin-api.service.ts

@@ -0,0 +1,117 @@
+import { HttpClient, HttpParams } from '@angular/common/http';
+import { Injectable, inject } from '@angular/core';
+
+import {
+  AssetResponse,
+  BuildJobResponse,
+  LoginResponse,
+  DeletePostResponse,
+  PostInput,
+  PostResponse,
+  PostStatus,
+  PostsResponse,
+  SlugResponse
+} from './models';
+
+@Injectable({ providedIn: 'root' })
+export class AdminApiService {
+  private readonly http = inject(HttpClient);
+  private readonly baseUrl = '/api/admin';
+
+  me() {
+    return this.http.get<{ user: LoginResponse['user'] }>(`${this.baseUrl}/me`, {
+      withCredentials: true
+    });
+  }
+
+  login(username: string, password: string) {
+    return this.http.post<LoginResponse>(
+      `${this.baseUrl}/login`,
+      { username, password },
+      { withCredentials: true }
+    );
+  }
+
+  logout() {
+    return this.http.post<{ ok: boolean }>(`${this.baseUrl}/logout`, {}, { withCredentials: true });
+  }
+
+  listPosts(status: PostStatus | '', limit?: number, offset?: number) {
+    let params = new HttpParams();
+    if (status) {
+      params = params.set('status', status);
+    }
+    if (limit) {
+      params = params.set('limit', String(limit));
+    }
+    if (offset) {
+      params = params.set('offset', String(offset));
+    }
+    return this.http.get<PostsResponse>(`${this.baseUrl}/posts`, {
+      params,
+      withCredentials: true
+    });
+  }
+
+  getPost(id: string) {
+    return this.http.get<PostResponse>(`${this.baseUrl}/posts/${id}`, {
+      withCredentials: true
+    });
+  }
+
+  createPost(input: PostInput) {
+    return this.http.post<PostResponse>(`${this.baseUrl}/posts`, input, {
+      withCredentials: true
+    });
+  }
+
+  updatePost(id: string, input: PostInput) {
+    return this.http.put<PostResponse>(`${this.baseUrl}/posts/${id}`, input, {
+      withCredentials: true
+    });
+  }
+
+  deletePost(id: string) {
+    return this.http.delete<DeletePostResponse>(`${this.baseUrl}/posts/${id}`, {
+      withCredentials: true
+    });
+  }
+
+  publishPost(id: string) {
+    return this.http.post<PostResponse & BuildJobResponse>(
+      `${this.baseUrl}/posts/${id}/publish`,
+      {},
+      { withCredentials: true }
+    );
+  }
+
+  buildPost(id: string) {
+    return this.http.post<BuildJobResponse>(
+      `${this.baseUrl}/posts/${id}/build`,
+      {},
+      { withCredentials: true }
+    );
+  }
+
+  getBuildJob(id: string) {
+    return this.http.get<BuildJobResponse>(`${this.baseUrl}/build-jobs/${id}`, {
+      withCredentials: true
+    });
+  }
+
+  uploadAsset(file: File) {
+    const body = new FormData();
+    body.append('file', file);
+    return this.http.post<AssetResponse>(`${this.baseUrl}/assets`, body, {
+      withCredentials: true
+    });
+  }
+
+  generateSlug(title: string, summary: string, postId?: string) {
+    return this.http.post<SlugResponse>(
+      `${this.baseUrl}/slug`,
+      { title, summary, postId },
+      { withCredentials: true }
+    );
+  }
+}