[#231] Fix page titles and empty og:image in header meta

[vharseko]

Summary

• Blog post <title> and og:title are built from the file slug (144 posts) #231 — 143 of 194 posts have only landing-title: in their front matter, so Jekyll fell back to a page.title derived from the file slug (Openam Vs Keycloak, Openam 16 1 2 Released). header.html now uses landing-title for posts when it is set — the same fallback structured-data.html already uses for the BlogPosting headline. No post has both fields, and the only non-post page with landing-title is index.html (landing: true), so other pages are unaffected.
• Site name duplicated in the page title of /forgerock-alternative #233 — removed the — Open Identity Platform suffix from the /forgerock-alternative title:; the template already appends the site name.
• Empty imageurl (from Missing openidm-og.png breaks social preview images on 6 OpenIDM posts #232 / Minor cleanups: unused blogposts.yml, file name with a space, outdated share links #238) — an empty string is truthy in Liquid, so imageurl: '' rendered og:image as …/assets/img/. header.html and the BlogPosting JSON-LD now treat an empty value as missing, and the empty line is removed from 2023-02-22-login-password-authentication.md.

Fixes #231
Fixes #233

Verification

Built the site with bundle exec jekyll build (Ruby 3.1, as in CI) and checked the output:

Page	Before	After
/blog/2025-12-18-openam-vs-keycloak	Openam Vs Keycloak · Open Identity Platform	OpenAM vs Keycloak · Open Identity Platform
/blog/2026-07-20-openam-16-1-2-released	Openam 16 1 2 Released · Open Identity Platform	OpenAM 16.1.2 Released · Open Identity Platform
/forgerock-alternative	ForgeRock Alternative & Migration Path — Open Identity Platform · Open Identity Platform	ForgeRock Alternative & Migration Path · Open Identity Platform
/	Open Source IAM & SSO	unchanged

• <title> of all 192 posts with a title: or landing-title: matches their front matter (the other two are the redirect copy and the file with a space in its name, tracked in Minor cleanups: unused blogposts.yml, file name with a space, outdated share links #238); og:title / twitter:title follow the same value.
• The login/password post now gets the default og:image instead of a broken /assets/img/ URL.

Not included: canonical: in 33 posts (#236) — pending a decision; the missing openidm-og.png (#232) needs an image.

[maximthomas]

praise: The title fix is limited to the pages that need it, and the empty-image guard covers both places that render the image.

• page.collection == "posts" and page.landing-title (_includes/header.html:6) switches only posts to landing-title, so the landing-title in index.html stays out of <title>.
• The page.imageurl != "" guard is in both og:image consumers: _includes/header.html:4 and the BlogPosting JSON-LD at _includes/structured-data.html:119.

---

issue (non-blocking): The login/password post's <title>, og:title and twitter:title now show the "Authenticaion" typo.

_posts/2023-02-22-login-password-authentication.md:3-4, _includes/header.html:6

The post has no title:, so header.html:6 now takes its landing-title, "Login and Password Authenticaion". Before this PR the page used Jekyll's slug title, "Login Password Authentication · Open Identity Platform", which is spelled correctly. Now the search-result title and the social card read "Login and Password Authenticaion · Open Identity Platform". This PR already edits that front matter, so the fix fits here.

landing-title: "Login and Password Authentication"
landing-title2: "Login and Password Authentication"

---

suggestion (non-blocking): Nothing in CI pins the post-title or the empty-og:image fix.

.github/workflows/build.yml:19-30

build.yml runs jekyll build and then htmlproofer --checks Links, which ignores absolute URLs. Neither step reads the <title>, og:title or twitter:title text, or the og:image URL. If the page.collection == "posts" branch were dropped, Openam Vs Keycloak · Open Identity Platform would come back and CI would stay green (reasoned, not run). The only evidence today is the manual build table in the description.

      - name: Check rendered head meta
        run: |
          grep -qF '<title>OpenAM vs Keycloak · Open Identity Platform</title>' _site/blog/2025-12-18-openam-vs-keycloak.html
          if grep -rlE --include='*.html' 'property="og:image" content="[^"]*/assets/img/"' _site; then exit 1; fi

Pin: the first line fails if the posts branch at header.html:6 is removed. The second fails if any page renders og:image as …/assets/img/ again. No page at this head has an empty imageurl, because the only imageurl: '' was removed, so nothing here exercises the != "" guard itself.