chore: add Cloud Agent development environment config

[DevSecTim]

Summary

Adds a Cloud Agent development environment so agents can run, build, and preview the Hugo site end to end. This mirrors the setup already used by the Azure Static Web Apps CI workflow (Hugo extended 0.147.1, PaperMod theme submodule).

Changes

• .cursor/environment.json — declares the environment: runs the reconciler script as both the install and start hooks, exposes port 1313, and starts a live-reload hugo server in a persistent terminal.
• .cursor/install.sh — idempotent reconciler that installs Hugo extended 0.147.1 (pinned to match CI) and initialises the PaperMod theme git submodule. Works from any working directory.

Why the reconciler runs as both install and start

On a prebuilt-snapshot boot the install hook is skipped, and a fresh default_checkout re-clones /workspace without submodules — which would leave themes/PaperMod/ empty. Running the same idempotent script as the per-boot start hook restores the submodule (and Hugo, if absent) on every boot. Hugo is pinned to the version CI uses (HUGO_VERSION: 0.147.1) to keep local and deployed builds consistent.

Validation

• ./.cursor/install.sh is idempotent and runs correctly from any working directory.
• Simulated the exact broken snapshot-boot state (Hugo removed, submodule de-initialised); the script self-heals — reinstalls Hugo and re-clones the theme submodule.
• On a completely fresh Cloud Agent VM, running the committed hook produced: hugo v0.147.1 +extended, a populated themes/PaperMod/ submodule, a successful hugo --gc --minify build (25 pages, 29 processed images), and a dev server returning HTTP 200 for the home, writings, search, and search-index (/index.json) routes.
• Browser walkthrough confirms the home/profile page, writings list, an individual post (with cover image), and live search all render correctly with the dark theme.

hugo-site-end-to-end-demo.mp4

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