feat(blog): add markdown blog sourced from a gitea repo

posts are markdown files with yaml frontmatter (title, slug, date;
optional draft/public) in the grenade/blog repo. the worker's new
BlogSource polls the repo — one branch-tip request when nothing
changed — and upserts posts into events with source='blog' and
occurred_at from the frontmatter date, so imported posts keep their
original publish dates and backfill the contribution graph.

- new /v1/blog and /v1/blog/{slug} endpoints over the existing
  EventReader port; drafts stay hidden via the public gate
- new /blog and /blog/:slug routes, nav link, activity-feed entry
  with post icon and filter toggle; relative image srcs resolve to
  gitea raw urls
- shared Markdown component extracted from ProjectPage
- vite proxy target overridable via API_PROXY_TARGET for local dev

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

crates/moments-api/src/main.rs

@@ -11,7 +11,7 @@ use chrono::{DateTime, Datelike, NaiveDate, Utc};
 use clap::Parser;
 use moments_core::{EventReader, reshape};
 use moments_data::PgStore;
-use moments_entities::{DailyCount, EventQuery, HourlyAvg, LanguageDailyCount, ProjectSummary, RepoLanguage, Source, SourceSummary, TimelineItem};
+use moments_entities::{BlogPost, BlogPostSummary, DailyCount, Event, EventQuery, HourlyAvg, LanguageDailyCount, ProjectSummary, RepoLanguage, Source, SourceSummary, TimelineItem};
 use serde::Deserialize;
 use tower_http::{cors::CorsLayer, trace::TraceLayer};
 use tracing::info;
@@ -56,6 +56,8 @@ async fn main() -> anyhow::Result<()> {
         .route("/v1/events", get(list_events))
         .route("/v1/sources", get(list_sources))
         .route("/v1/projects", get(list_projects))
+        .route("/v1/blog", get(list_blog_posts))
+        .route("/v1/blog/{slug}", get(get_blog_post))
         .route("/v1/activity/daily", get(daily_counts))
         .route("/v1/activity/hourly", get(hourly_avgs))
         .route("/v1/languages/daily", get(language_daily_counts))
@@ -144,6 +146,61 @@ async fn list_projects(
     Ok(Json(projects))
 }
 
+/// All public blog events, newest first. Blog posts live in the events
+/// table (`source = 'blog'`); the payload carries the frontmatter fields
+/// and the full markdown body.
+async fn blog_events(state: &AppState) -> Result<Vec<Event>, ApiError> {
+    let query = EventQuery {
+        sources: Some(vec![Source::Blog]),
+        // Drafts are stored with public = false and stay invisible here.
+        include_private: false,
+        limit: 1000,
+        ..Default::default()
+    };
+    state.store.list_events(&query).await.map_err(internal)
+}
+
+fn payload_str<'a>(event: &'a Event, key: &str) -> &'a str {
+    event.payload.get(key).and_then(|v| v.as_str()).unwrap_or("")
+}
+
+async fn list_blog_posts(
+    State(state): State<AppState>,
+) -> Result<Json<Vec<BlogPostSummary>>, ApiError> {
+    let posts = blog_events(&state)
+        .await?
+        .iter()
+        .map(|ev| BlogPostSummary {
+            slug: payload_str(ev, "slug").to_string(),
+            title: payload_str(ev, "title").to_string(),
+            published_at: ev.occurred_at,
+            excerpt: moments_core::presentation::blog::excerpt(payload_str(ev, "markdown")),
+        })
+        .collect();
+    Ok(Json(posts))
+}
+
+async fn get_blog_post(
+    State(state): State<AppState>,
+    Path(slug): Path<String>,
+) -> Result<Json<BlogPost>, ApiError> {
+    let id = format!("blog:{slug}");
+    let events = blog_events(&state).await?;
+    let ev = events.iter().find(|ev| ev.id == id).ok_or(ApiError {
+        status: StatusCode::NOT_FOUND,
+        message: "no such post".into(),
+    })?;
+    Ok(Json(BlogPost {
+        slug: payload_str(ev, "slug").to_string(),
+        title: payload_str(ev, "title").to_string(),
+        published_at: ev.occurred_at,
+        markdown: payload_str(ev, "markdown").to_string(),
+        host: payload_str(ev, "_host").to_string(),
+        repo: payload_str(ev, "_repo").to_string(),
+        branch: payload_str(ev, "_branch").to_string(),
+    }))
+}
+
 #[derive(Debug, Deserialize)]
 struct DailyCountsParams {
     from: Option<NaiveDate>,