feat(docs): guided start pages and landing UX for Drupal workspaces

[jameswilson]

Fixes #156

Summary

Users landing on start.coder.ddev.com were often sent straight to the raw drupal-core Coder template in manual mode, where version/branch mismatches and opaque parameter choices caused confusion. This PR steers people through guided entry points on the start site, consolidates shared styling, and prefills workspace creation via mode=auto so the right template parameters are locked in before Coder opens.

Landing page (docs/index.html)

• Replaces the old single-call-to-action layout with a three-column tile grid: Drupal Issue (recommended), Drupal Core, and DDEV Freeform
• Adds footnote-linked callouts for stability expectations and GitHub OAuth access requirements
• Moves sign-in guidance below the primary tiles in a muted callout with GitHub icon
• Links “How it works” and resources to the new guided pages instead of raw template URLs
• Fixes the Drupal Core tile to point at /drupal-core (not /drupal-issue)
• Fixes malformed footnote markup (stray closing </a>)

New guided start pages

/drupal-core (docs/drupal-core.html)

• New page for vanilla Drupal core workspaces (no issue fork)
• Pick-card radios for Drupal version (10/11/12), install profile (Demo Umami / Minimal / Standard), and site visibility
• Editable workspace name with live URL slug preview
• Launches coder/drupal-core with mode=auto and disable_params so version, profile, and visibility are prefilled and not accidentally changed in Coder

/drupal-issue (docs/drupal-issue.html)

• Major refactor aligned with the drupal-core page layout and copy
• Accepts issue number, drupal.org issue/project URL, or contrib machine name
• Issue flow: fetches issue metadata from drupal.org, loads branches from git.drupalcode.org, auto-selects the most recently committed branch, and chooses drupal-core vs drupal-contrib template automatically
• Plain contrib flow: verify project on git.drupalcode.org, then launch HEAD development without an issue fork
• Manual fallback form when APIs fail (fork name, branch, version, profile, visibility)
• Pick-card fields replace <select> dropdowns for version, profile, and site visibility (matches drupal-core)
• Launches with mode=auto + disable_params on all three forms (result, plain, manual)
• Theme support: resolves param.project_type (module vs theme) from the Drupal.org project node API (project_theme / project_module) so contrib themes symlink into web/themes correctly
• Template badge shows project type for contrib issues

Shared infrastructure

docs/coder-ddev-start.css

• New shared design system for the start site (~1500 lines): dark hero, tile grid, pick-cards, callouts, form fields, status messages, footnotes, accessibility helpers
• Component classnames are prefixed with .cds- namespace.
• Replaces large inline <style> blocks previously duplicated across pages

docs/coder-workspace-name.js

• Shared workspace name sanitization and suggestion helpers
• 32-character Coder workspace name limit with inline field validation before launch
• Branch-based names fall back to issue NID when {version}-{profile}-{branch} would exceed the limit

docs/components.html

• Internal component gallery documenting pick-cards, tiles, callouts, and form patterns used on the start site

Layout consolidation

• docs/_layouts/default.html, docs/access-denied.html — drop inline CSS in favor of shared stylesheet
• New logo assets: docs/logo-coder-on-dark.svg, docs/logo-ddev-on-dark.svg

Documentation updates

docs/user/quickstart.md

• Replaces raw “Open in Coder” button with guided tile links to /drupal-issue and /drupal-core
• Adds guidance about confirming workspace creation in Coder vs editing locked parameters
• Links code layout sections to ddev-drupal-dev and ddev-drupal-contrib add-on documentation via announce callouts

README.md

• Replaces single manual template badge with recommended paths (issue picker, freeform, guided core, template browser) and an advanced manual link

Template tweak (requires separate template push)

drupal-core/template.tf

• Human-readable install profile option labels (Demo Umami, Minimal, Standard)
• Clearer install profile description explaining Demo Umami snapshot behavior on Drupal 12 vs full installs on other profiles/versions

Note: The template.tf label/description changes only take effect after the template is pushed to Coder; the start-site UX changes deploy with GitHub Pages.

Test plan

• Load start.coder.ddev.com/ — three tiles render; Core tile goes to /drupal-core; footnotes link and scroll correctly
• /drupal-core — pick version/profile/visibility, launch URL contains mode=auto and expected param.* values
• /drupal-issue — core issue (e.g. drupal.org core issue NID): loads branches, launches drupal-core template
• /drupal-issue — contrib module issue: launches drupal-contrib with param.project_type=module
• /drupal-issue — contrib theme (e.g. olivero or theme issue): launches with param.project_type=theme
• /drupal-issue — plain contrib machine name: plain-dev form, correct project type in URL
• Workspace name > 32 chars blocked with inline error; branch-based fallback uses NID
• Jekyll quickstart page renders tile HTML and announce callouts
• terraform fmt / validate on drupal-core if template push is included in this release

[jameswilson]

Screenshots:

Homepage

URL: /

Drupal Issue (empty)

URL: /drupal-issue

Drupal Issue (fork)

Drupal Issue (project)

Drupal Core

URL: /drupal-core

Quick start

URL: /user/quickstart

[rfay]

This is great. Would you mind just dropping the middle one for simplicity, assuming people don't actually need a drupal HEAD build?