fix(hosting): self-contained module CSS imports + cross-module npm-name imports (#253)

[antosubash]

Fixes #253 — both problems in it.

1. Module CSS imports broke every pre-0.0.27 host

gen-pages emitted @import "#module/<pkg>/styles.css" into modules.generated.css. That specifier resolves only if the host's vite.config.ts defines a matching resolve.alias — but that file is scaffold output: written into an app once, then owned and edited there. It's versioned independently of the Python packages, so upgrading simple_module_* 0.0.26 → 0.0.27 broke vite build in every app scaffolded earlier, on a specifier appearing nowhere in the app's own sources.

Fix: emit absolute paths, exactly as the @source lines in the same file already did. The "ugly ../../../.venv/... path" objection only ever applied to relative ones. modules.generated.css is now self-contained and needs no host cooperation.

This is suggestion (1) from the issue, and it subsumes (2) and (3): with nothing to resolve, there's no host config to verify and no doctor check to add. No host action required.

2. Cross-module TS imports by npm package name

Now supported: import { X } from '@simple-module-py/pagebuilder/components/blockRegistry'.

gen-pages records each module's npm_name in modules.assets.json; the host aliases it onto the module's Python package directory.

That anchor is forced, not chosen — I confirmed it by inspecting a real built wheel, which contains dashboard/** and nothing above it. Hatch force-includes the module-root package.json into the package, so the source-tree module root doesn't survive installation, and the package dir is the only anchor both layouts share:

import x from '@simple-module-py/foo/components/Widget';      // ✅ both layouts
import x from '@simple-module-py/foo/foo/components/Widget';  // ❌ workspace-only

The second shape is what npm's symlink gives you for a workspace member — which is exactly why a hand-rolled alias against the module root appears to work in a checkout and breaks once the module is wheel-installed.

⚠️ This half does require a vite.config.ts change in existing hosts — unlike the CSS fix, the import lives in module source rather than a generated file, so it can't be made self-contained. The CHANGELOG carries the diff. New scaffolds get it automatically, and the new template degrades gracefully against 0.0.27 packages (no npm_name → no alias → no crash), which I verified.

Correcting the issue's diagnosis

The issue attributes this to the template removing package-name aliases and to the #156 fix being unreleased. Both are wrong, and suggestion (4) rests on them:

• git diff v0.0.26 v0.0.27 on the template is purely additive — no alias block was ever in the framework template.
• The v0.0.13 cross-package fix doesn't cover workspace-member modules + dep-scan still errors #156 fix (c42d615) has shipped since v0.0.15. Only its CHANGELOG entry was stale, which is how the issue reached the opposite conclusion.

So rather than re-landing something that was never removed, this adds the capability properly, with an anchor that works in both install layouts.

Verification

Measured, not assumed:

Check	Result
Absolute @import, vite 6.4.3 + @tailwindcss/vite 4.3.3, no alias configured	resolves
Alias @import, same stack, no alias (negative control)	fails with the reporter's exact error
Repo build with resolve.alias forced to []	module CSS reaches the bundle
Dev server	module CSS served
Module dir entirely outside the project root, styles.css + unlayered @theme	both resolve
Real smpy new app (vite 6): workspace module imports a wheel-installed module by npm name	builds; sibling component lands in the chunk
Same app, new template + 0.0.27 packages	builds (graceful degradation)
Cross-module import with the alias removed	fails — so the new test isn't vacuous
make lint / make test	clean — 1760 Python, 48 JS

New guards: test_generated_css_is_self_contained (every @import absolute, non-aliased, exists on disk), a real-build test that a cross-module npm-name import resolves, and unit coverage for both install layouts, the pyproject.toml guard, malformed package.json, and npm-name uniqueness.

Also in here

• biome.json — exclude modules.generated.css / modules.assets.json, matching the exclusions already there for the other two generated files. Absolute paths are long, so whether a line exceeded biome's 100-char lineWidth depended on where the repo was checked out: make lint passed or failed by directory path. Caught by lint, not inspection.
• CHANGELOG.md — moved the Vite dev-server scan-imports fails to resolve cross-package bare imports from module pages #152 / fix(vite): seed esbuild nodePaths so scan-imports resolves bare imports from module pages #155 / v0.0.13 cross-package fix doesn't cover workspace-member modules + dep-scan still errors #156 / Login success redirects to / (404) instead of /dashboard #173 entries out of [Unreleased] into the releases that actually shipped them (verified with git tag --contains), and documented the 0.0.27 regression with a manual workaround for anyone pinned there.
• Structural (300-line cap, per CLAUDE.md's "split by responsibility" — both files were already at the edge): host/client_app/module-assets.ts lifts module discovery out of vite.config.ts, mirroring the existing compress-assets.ts split; npm-identity tests move to their own file with the importable-module factory shared via a tests/conftest.py fixture.

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