fix(imaging): support .hab assets, cache avatars/badges, harden routes

The hotel moved from .nitro to .hab bundles, so the imager must treat .hab
like .nitro and the public avatar endpoints must accept the figure strings
the client sends (including extra trailing segments such as `.0`, which the
old FIGURE_RE rejected with a 400).

- imager-upstream: relax FIGURE_RE, extend parseAvatarQuery test coverage
- api/imaging/avatar + /imaging: shared validation, placeholder and ETag/304
- api/imaging/badge: single-flight upstream fetch and conditional responses
- imager-http/imager-png: strong ETag helpers and APNG passthrough guard
- csp + next/image: unoptimized external images, tightened CSP
- deps: override postcss-selector-parser to ^7.1.6
- also fold in the pending drizzle draft snapshot and stray test cleanup

pnpm-workspace.yaml

@@ -17,3 +17,8 @@ overrides:
   '@esbuild-kit/core-utils': 'npm:tsx@^4.23.15'
   '@esbuild-kit/esm-loader': 'npm:tsx@^4.23.15'
   source-map-js: '1.2.2'
+  # GHSA advisory: postcss-selector-parser <7.1.6. Pulled in only by
+  # @tailwindcss/typography (build-time prose selectors), which pins 6.0.10
+  # exactly and has no upstream bump. The API subset it uses is unchanged in
+  # v7, so force the patched major.
+  postcss-selector-parser: '^7.1.6'