…-*-page components

The blog/library split (#5516) moved the blog post/index/author JSX into
shared ContentPostPage/ContentIndexPage/ContentAuthorPage components while
this branch was in flight, so the original unoptimized removal (verified
local-only ogImage paths for both blog and library content) needs to land
on those shared components instead of the old per-route JSX.

… pages (#5522)

* fix(landing): fix Core Web Vitals regressions across public marketing pages

- root layout unconditionally rendered next-runtime-env's PublicEnvScript,
  which calls unstable_noStore() and silently forced every route in the app
  dynamic - marketing pages never got static/ISR caching despite their own
  revalidate. Gated it to self-hosted only; hosted now uses a static,
  build-time equivalent (app/_shell/public-env-script.tsx)
- removed real pointer-drag handlers from the hero's decorative workflow
  animation (was draggable despite being aria-hidden)
- disabled dragging/panning on the (currently unmounted) landing-preview
  ReactFlow canvas so it's static-by-default if it's ever wired in
- lazy-mount the Product Demo section's duplicate HeroVisual instance via
  next/dynamic + IntersectionObserver instead of loading it eagerly below
  the fold
- disabled Next.js Link prefetch on always-in-viewport /signup and /login
  CTAs (navbar, hero, mobile nav) so their JS isn't fetched on every
  pageview regardless of whether the visitor clicks
- removed `unoptimized` from local blog/integration images (including the
  priority LCP image on every blog post), letting next/image serve
  resized AVIF/WebP instead of full-size originals

* fix(landing): address review findings on the CWV PR

- revert prefetch={false} on below-fold CTAs (cta.tsx, enterprise.tsx) -
  contradicts the prefetch-on-approach rule this PR itself documents
- restore unoptimized on avatarUrl and the MDX body-image renderer, both of
  which can legitimately hold external URLs outside next.config.ts's
  image remotePatterns allow-list
- simplify handleAnchors to a single block argument now that positions are
  static (the second "live position" argument was always identical to the
  first after the drag-handler removal)
- extract the near-duplicate IntersectionObserver lazy-mount logic shared
  by landing-preview-mount.tsx and product-demo-visual-mount.tsx into a
  single apps/sim/app/(landing)/hooks/use-lazy-mount.ts hook
- import next-runtime-env's own exported PUBLIC_ENV_KEY constant instead of
  a hardcoded string literal, and match its case-insensitive NEXT_PUBLIC_
  filter exactly, removing any drift risk between the two implementations
- drop plain inline comments with no TSDoc home in favor of relying on the
  existing TSDoc/CLAUDE.md documentation

* fix(landing): carry the unoptimized-image fix onto the shared content-*-page components

The blog/library split (#5516) moved the blog post/index/author JSX into
shared ContentPostPage/ContentIndexPage/ContentAuthorPage components while
this branch was in flight, so the original unoptimized removal (verified
local-only ogImage paths for both blog and library content) needs to land
on those shared components instead of the old per-route JSX.

* fix(landing): document ogImage's local-path expectation, fix CLAUDE.md structure doc

- add a one-line comment on ContentFrontmatterSchema.ogImage documenting
  that it's rendered without unoptimized and expects a local path, matching
  the existing avatarUrl comment convention (a reviewer noted ogImage's
  schema is technically unconstrained and seo.ts has an http-prefix branch,
  though all current content is local)
- add the new hooks/ folder to the (landing) CLAUDE.md structure diagram and
  name use-lazy-mount.ts directly in the lazy-mount rule

* fix(landing): escape </script> breakout in the static public-env script

Greptile P1: a NEXT_PUBLIC_* value containing "</script>" would close the
inline script early and could inject markup/script into every hosted page.
Escape "<" in the serialized JSON before interpolating it, matching the
standard JSON-in-script-tag safeguard.