feat: add leaderboard router, gamification backfill, and shared content creation helpers

Introduce a new `/leaderboard` endpoint ranking top 50 members by total stars, wire it into the app router and documentation. Implement `_backfill_gamification()` in `database.py` to compute XP/levels for existing accounts from prior posts, comments, votes, and follows. Extract `is_owner()`, `create_content_item()`, and `detail_context()` into `content.py` to centralize content creation, reward awarding, mention notifications, and attachment linking. Update comment creation/deletion in `comments.py` to use `award_rewards()` with `XP_COMMENT` and the new `is_owner()` helper. Add shared template partials documentation for vote bars, star buttons, post headers, and topic selectors to `AGENTS.md`.

devplacepy/routers/gists.py

@@ -1,14 +1,13 @@
 import logging
 from typing import Annotated
-from datetime import datetime, timezone
-from fastapi import APIRouter, Request, HTTPException, Form
+from fastapi import APIRouter, Request, Form
 from devplacepy.models import GistForm, GistEditForm
 from fastapi.responses import HTMLResponse, RedirectResponse
 from devplacepy.database import get_table, get_users_by_uids, get_gist_languages
-from devplacepy.content import load_detail, edit_content_item, delete_content_item, enrich_items
+from devplacepy.content import load_detail, edit_content_item, delete_content_item, enrich_items, create_content_item, detail_context
 from devplacepy.templating import templates
-from devplacepy.utils import generate_uid, get_current_user, require_user, make_combined_slug, create_mention_notifications
-from devplacepy.seo import base_seo_context, site_url, website_schema, software_source_code_schema
+from devplacepy.utils import get_current_user, require_user, not_found, XP_GIST
+from devplacepy.seo import base_seo_context, site_url, website_schema, software_source_code_schema, list_page_seo
 
 logger = logging.getLogger(__name__)
 router = APIRouter()
@@ -24,7 +23,7 @@ LANGUAGES = [
 ]
 
 
-def get_gists_list(user_uid=None, language=None):
+def get_gists_list(user_uid=None, language=None, viewer=None):
     gists_table = get_table("gists")
     filters = {}
     if user_uid:
@@ -38,16 +37,15 @@ def get_gists_list(user_uid=None, language=None):
         return []
 
     users_map = get_users_by_uids([g["user_uid"] for g in all_gists])
-    return enrich_items(all_gists, "gist", users_map)
+    return enrich_items(all_gists, "gist", users_map, user=viewer)
 
 
 @router.get("", response_class=HTMLResponse)
 async def gists_page(request: Request, language: str = None, user_uid: str = None):
     user = get_current_user(request)
-    gists_data = get_gists_list(user_uid, language)
+    gists_data = get_gists_list(user_uid, language, viewer=user)
     total_count = len(gists_data)
-    base = site_url(request)
-    seo_ctx = base_seo_context(
+    seo_ctx = list_page_seo(
         request,
         title="Gists",
         description=f"Browse {total_count} code snippets on DevPlace.",
@@ -55,7 +53,6 @@ async def gists_page(request: Request, language: str = None, user_uid: str = Non
             {"name": "Home", "url": "/feed"},
             {"name": "Gists", "url": "/gists"},
         ],
-        schemas=[website_schema(base)],
     )
     return templates.TemplateResponse(request, "gists.html", {
         **seo_ctx,
@@ -74,7 +71,7 @@ async def gist_detail(request: Request, gist_slug: str):
     user = get_current_user(request)
     detail = load_detail("gists", "gist", gist_slug, user)
     if not detail:
-        raise HTTPException(status_code=404, detail="Gist not found")
+        raise not_found("Gist not found")
     gist = detail["item"]
 
     base = site_url(request)
@@ -90,19 +87,9 @@ async def gist_detail(request: Request, gist_slug: str):
         ],
         schemas=[website_schema(base), software_source_code_schema(gist, base)],
     )
-    return templates.TemplateResponse(request, "gist_detail.html", {
-        **seo_ctx,
-        "request": request,
-        "user": user,
-        "gist": gist,
-        "author": detail["author"],
-        "is_owner": detail["is_owner"],
-        "star_count": detail["star_count"],
-        "time_ago": detail["time_ago"],
-        "comments": detail["comments"],
+    return templates.TemplateResponse(request, "gist_detail.html", detail_context(request, user, detail, "gist", seo_ctx, {
         "languages": LANGUAGES,
-        "attachments": detail["attachments"],
-    })
+    }))
 
 
 @router.post("/create")
@@ -117,27 +104,12 @@ async def create_gist(request: Request, data: Annotated[GistForm, Form()]):
     if language not in valid_languages:
         language = "plaintext"
 
-    gists = get_table("gists")
-    uid = generate_uid()
-    gist_slug = make_combined_slug(title, uid)
-    gists.insert({
-        "uid": uid,
-        "user_uid": user["uid"],
+    uid, gist_slug = create_content_item("gists", "gist", user, {
         "title": title,
-        "slug": gist_slug,
         "description": description or None,
         "source_code": source_code,
         "language": language,
-        "stars": 0,
-        "created_at": datetime.now(timezone.utc).isoformat(),
-    })
-
-    from devplacepy.attachments import link_attachments
-    link_attachments(data.attachment_uids, "gist", uid)
-
-    create_mention_notifications(description or "", user["uid"], f"/gists/{gist_slug}")
-
-    logger.info(f"Gist {uid} created by {user['username']}")
+    }, title, XP_GIST, "First Gist", description or "", data.attachment_uids)
     return RedirectResponse(url=f"/gists/{gist_slug}", status_code=302)