Add Coach mode C5: post news, reusing the desktop's own NewsForm

management.forms.NewsForm defaults its teams field to every club team --
fine for an editor/admin, but a real gap for a coach, who should only ever
post as their own team, never "on behalf of" one they don't run. Re-scoped
to teams_managed_by via self.managed_teams, and made required (a coach's
post is always team-scoped, never empty/club-wide -- that stays an
editor/admin claim).

Gated with club.services.access.can_add_news, which already includes
is_coach_manager. On submit the post goes straight to
News.submit_for_review() plus the same notify_editors_of_pending_review
call the desktop's own NewsSubmitForReviewView makes, landing in an
editor's queue instead of a silent draft. The button reads "Send" rather
than the mock's "Publish" -- can_publish_news stays editor/admin-only, so
that's the honest description of what actually happens.

visibility is left at the model's own INTERNAL default rather than
building the mock's "also on club website" toggle -- an editor reviewing
the pending post can widen it before publishing if a public-site
placement is actually warranted; that's a real gate, not a decorative
row, so it isn't reproduced as one here.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01ECGMEwrc2k4D8VQuwjstj9

mobile/templates/mobile/coach/news_form.html

@@ -0,0 +1,58 @@
+{% extends "mobile/coach/base.html" %}
+{% load i18n %}
+
+{% comment %}
+    C5 -- design_handoff_rosterchief_platform/README.md's C5 section: title,
+    body, and which of the coach's own teams this is for. See
+    CoachCreateNewsView's own docstring for what's scoped down from the mock
+    (no cover photo -- News has no such field; no English fallback; no
+    audience/visibility toggle) and why the button reads "Send for review"
+    rather than the mock's "Publish" -- a coach's post always needs an
+    editor's sign-off first.
+{% endcomment %}
+
+{% block content %}
+    <div class="-mx-4 -mt-5 flex items-center gap-3 border-b border-line bg-white px-4 py-3">
+        <a class="font-display text-sm font-extrabold tracking-wide text-muted uppercase" href="{% url "mobile:coach_today" %}">{% trans "Cancel" %}</a>
+        <span class="min-w-0 flex-1 truncate text-center font-display text-lg font-extrabold text-ink uppercase">{% trans "New post" %}</span>
+        <button class="font-display text-sm font-extrabold tracking-wide text-club uppercase" type="submit" form="coach-news-form">{% trans "Send" %}</button>
+    </div>
+
+    {% if form.non_field_errors %}
+        <div class="m-card border border-danger-border bg-danger-bg p-3 text-sm text-club-dark">
+            {% for error in form.non_field_errors %}<p>{{ error }}</p>{% endfor %}
+        </div>
+    {% endif %}
+
+    <form id="coach-news-form" method="post" action="{% url "mobile:coach_create_news" %}">
+        {% csrf_token %}
+
+        <div class="m-card flex flex-col p-4">
+            <div>
+                <label class="mb-1 block text-xs font-semibold text-muted" for="{{ form.title.id_for_label }}">{% trans "Headline" %}</label>
+                {{ form.title }}
+                {% for error in form.title.errors %}<p class="mt-1 text-xs text-club-dark">{{ error }}</p>{% endfor %}
+            </div>
+            <div class="my-3 h-px bg-rule"></div>
+            <div>
+                <label class="mb-1 block text-xs font-semibold text-muted" for="{{ form.body.id_for_label }}">{% trans "Body" %}</label>
+                {{ form.body }}
+                {% for error in form.body.errors %}<p class="mt-1 text-xs text-club-dark">{{ error }}</p>{% endfor %}
+            </div>
+        </div>
+
+        <div class="m-card p-4">
+            <div class="mb-2 font-display text-xs font-extrabold tracking-wide text-muted uppercase">{% trans "Audience" %}</div>
+            <div class="flex flex-col gap-2">
+                {% for checkbox in form.teams %}
+                    <label class="flex items-center gap-2 text-sm text-ink">
+                        {{ checkbox.tag }}
+                        {{ checkbox.choice_label }}
+                    </label>
+                {% endfor %}
+            </div>
+            {% for error in form.teams.errors %}<p class="mt-1 text-xs text-club-dark">{{ error }}</p>{% endfor %}
+            <p class="mt-2 text-xs text-dim">{% trans "Sent to an editor for review before it goes out to families." %}</p>
+        </div>
+    </form>
+{% endblock content %}

mobile/templates/mobile/coach/today.html

@@ -17,7 +17,10 @@
         </div>
     {% else %}
         {% if can_manage_active_team %}
-            <a class="btn btn-dark w-full" href="{% url "mobile:coach_create_event" %}">{% trans "New event" %}</a>
+            <div class="flex gap-2">
+                <a class="btn btn-dark flex-1" href="{% url "mobile:coach_create_event" %}">{% trans "New event" %}</a>
+                <a class="btn btn-secondary flex-1" href="{% url "mobile:coach_create_news" %}">{% trans "New post" %}</a>
+            </div>
         {% endif %}
 
         <div class="grid grid-cols-3 gap-2.5">