Redirect create actions with 303 See Other so Turbo advances

[maebeale]

🤖 suggested review level: 3 Read 📖 one-line status change on 6 create redirects + a request spec each

Fixes a Turbo bug where a successful create didn't advance the page: the record saved but the user stayed on the form, so re-clicking Save produced duplicate records.

• Why: Turbo Drive needs a 303 See Other (not 302) to navigate after a form POST. These create actions redirected with a plain 302, so Turbo didn't move on. The update actions already used :see_other — this just aligns create to match.
• Added status: :see_other to the create-success redirect in community_news, stories, events, workshops, resources, video_recordings, each with a request spec asserting 303.

Scope

• The same 302-after-POST gap exists on other create/destroy actions across the app (e.g. organizations, grants, people, features, sectors…). This PR fixes the content-form controllers where the duplicate-record symptom was reported. Happy to do a broader sweep in a follow-up if wanted — a blanket change is avoided here because some of those redirects are guard/error paths where 303 isn't the right call.