docs: rebuild the documentation homepage around its readers

The homepage showed a screenshot of the web app's landing page beside a heading the screenshot
already contained, so the tagline appeared twice. The asset pipeline now exports the scene alone —
the four cards of one change and the feedback attached to them — and both the README and the docs
site use that instead.

Around it the page becomes a documentation homepage rather than a compressed marketing one: search
is visible where a visitor lands, the pre-1.0 support window is stated in an announcement bar
instead of only inside the compatibility policy, and each guide card names its audience and links
the pages that audience opens first.

Also: the exact mentor accent from the web app, themed shadows that survive dark mode, an accessible
heading for the feature section, imprint and privacy in the footer, descriptions on twelve pages that
had none, and the removal of the unused template sidebar, seven orphaned screenshots and the
sidebar_position frontmatter that ordered nothing and contradicted itself.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

Author: FelixTJDietrich

README.md

@@ -31,11 +31,11 @@ replace mentors: the harder judgement and the relationships stay with people.
 
 <div align="center">
   <picture>
-    <source media="(prefers-color-scheme: dark)" srcset="./docs/images/readme/landing-hero-dark.png">
-    <source media="(prefers-color-scheme: light)" srcset="./docs/images/readme/landing-hero-light.png">
-    <img alt="An illustration of one change through a project: issue #412 has no acceptance criteria, the pull request grew to 34 files and picked up an unrelated rename, a reviewer asks a good question, and it merges with that thread unresolved. Hephaestus points back to the issue." src="./docs/images/readme/landing-hero-light.png" width="1280">
+    <source media="(prefers-color-scheme: dark)" srcset="./docs/images/readme/feedback-scene-dark.png">
+    <source media="(prefers-color-scheme: light)" srcset="./docs/images/readme/feedback-scene-light.png">
+    <img alt="Four cards from one change — an issue with no acceptance criteria, a pull request that grew to 34 files, a review question, and the merge that left it unanswered — each with the practice feedback Hephaestus attached to it." src="./docs/images/readme/feedback-scene-light.png" width="896">
   </picture>
-  <p><sub>An illustration of the kind of feedback Hephaestus writes. See the <a href="https://ls1intum.github.io/Hephaestus/user/ai-code-review">user guide</a> for the real interface.</sub></p>
+  <p><sub>An illustration of the feedback Hephaestus writes. See the <a href="https://ls1intum.github.io/Hephaestus/user/ai-code-review">user guide</a> for the real interface.</sub></p>
 </div>
 
 > [!IMPORTANT]
@@ -127,5 +127,5 @@ quality checks, and open a pull request. Participation in the project is governe
 Hephaestus is an [MIT-licensed](./LICENSE) open-source project developed by
 [Applied Education Technologies](https://aet.cit.tum.de/) at the
 [Technical University of Munich](https://www.tum.de/en/). It is named after the Greek god of the
-forge. In the myth Plato tells, his craft was carried out of the workshop and handed to people so
-they could build for themselves — which is roughly the idea here.
+forge, whose craft — in the myth Plato tells — was stolen from his workshop and given to people so
+they could make things for themselves.

docs/admin/ai-providers.mdx

@@ -1,6 +1,5 @@
 ---
 id: ai-providers
-sidebar_position: 2
 title: Connect an AI Provider
 description: Register an OpenAI-compatible provider, test it, price its models, and share them — field by field, with what a failed probe actually means.
 ---

docs/admin/backup-restore.mdx

@@ -1,6 +1,5 @@
 ---
 id: backup-restore
-sidebar_position: 3
 title: Backup & Restore
 description: What to back up on a self-hosted instance, and how to restore it.
 ---

docs/admin/buildpacks-cds-decision.md

@@ -1,7 +1,6 @@
 ---
 id: buildpacks-cds-decision
 title: Server image build via Paketo Buildpacks + Application CDS
-sidebar_position: 4
 description: How and why the application-server image is built with Paketo Cloud Native Buildpacks + Application CDS, and the Java 25 + JEP 483 migration path.
 ---
 

docs/admin/compatibility-policy.mdx

@@ -1,6 +1,5 @@
 ---
 id: compatibility-policy
-sidebar_position: 2
 title: Compatibility Policy
 description: What a Hephaestus version number promises — the public contract, upgrade guarantees, and support statement.
 ---

docs/admin/github-integration.mdx

@@ -1,6 +1,5 @@
 ---
 id: github-integration
-sidebar_position: 2
 title: GitHub Integration
 description: OAuth App for login, PAT or GitHub App for data access, and manual webhook setup.
 ---

docs/admin/install.mdx

@@ -1,6 +1,5 @@
 ---
 id: install
-sidebar_position: 0
 title: Install (Self-Hosted)
 description: The one supported way to run your own Hephaestus — Docker Compose on a single host.
 ---

docs/admin/legal-pages.mdx

@@ -1,6 +1,5 @@
 ---
 id: legal-pages
-sidebar_position: 2
 title: Legal Pages (Imprint & Privacy)
 description: How Hephaestus resolves the /imprint and /privacy pages, and what the operator of a self-hosted deployment is responsible for.
 ---

docs/admin/overview.mdx

@@ -1,6 +1,5 @@
 ---
 id: overview
-sidebar_position: -1
 title: Admin overview
 description: What a Hephaestus deployment consists of and the order to set it up in.
 ---

docs/admin/practice-catalog.mdx

@@ -1,6 +1,5 @@
 ---
 id: practice-catalog
-sidebar_position: 4
 title: Practice Catalog
 description: Curate the practices an instance offers, adopt them into a workspace, and read the badges that say when a workspace copy and the catalog have drifted apart.
 ---