docs: add block/mute user relations, emoji-sync CLI, and uid indexes

- Add `/block`, `/mute` endpoints with block/unblock and mute/unmute functionality in `routers/relations.py`, hiding blocked users' content everywhere except their own profile while muting only suppresses notifications
- Introduce `devplace emoji-sync` CLI command to regenerate `static/js/emoji-shortcodes.js` from the emoji library, documented in `CLAUDE.md` and wired in `cli.py`
- Create `get_blocked_uids()` database helper and apply it in `content.py` `load_detail()` to filter blocked users' posts from detail views
- Implement `_uid_index()` and `_drop_index()` helpers in `database.py` for unique uid indexes across tables, with `user_relations` added to `SOFT_DELETE_TABLES`
- Document new routes in `AGENTS.md` and `README.md`, including emoji shortcodes rendering behavior distinct from the emoji picker

devplacepy/templates/issue_detail.html

@@ -13,7 +13,7 @@
         <div class="issue-detail-header">
             <span class="issue-number">#{{ issue.number }}</span>
             <h1 class="issue-detail-title">{{ render_title(issue.title) }}</h1>
-            <span class="issue-status {{ issue.state }}">{{ issue.state }}</span>
+            <span class="issue-status {{ issue.state }}"><span class="sr-only">Status: </span>{{ issue.state }}</span>
         </div>
         <div class="issue-meta">
             {% if issue.is_local_author %}
@@ -51,7 +51,7 @@
                 {% if comment.is_local_author %}
                 {% set _user = {'username': comment.author_username} %}{% set _size = 20 %}{% set _size_class = "sm" %}{% include "_avatar_link.html" %}
                 {% else %}
-                <span class="issue-comment-badge">dev</span>
+                <span class="issue-comment-badge"><span class="sr-only">Developer reply from </span>dev</span>
                 {% endif %}
                 <span class="issue-author">{{ comment.author_username }}</span>
                 <span class="issue-dot">&middot;</span>
@@ -65,7 +65,7 @@
 
         {% if can_comment %}
         <form method="POST" action="/issues/{{ issue.number }}/comment" class="comment-form issue-comment-form">
-            <textarea name="body" required maxlength="5000" placeholder="Add a comment (posted to the tracker)..." class="min-h-120" data-mention></textarea>
+            <textarea name="body" required aria-required="true" maxlength="5000" placeholder="Add a comment (posted to the tracker)..." class="min-h-120" data-mention aria-label="Add a comment"></textarea>
             <div class="issue-comment-form-footer">
                 <button type="submit" class="btn btn-primary btn-sm"><span class="btn-spinner" aria-hidden="true"></span>Comment</button>
             </div>