Default to lean case aliases and repair Blazor CSS artifacts

[magiccodingman]

What changed

• make single-segment case aliases the default instead of generating the Cartesian product of case variants across every route segment
• retain the previous exhaustive alias behavior as an explicit option through SnapshotCaseAliasStrategy.Exhaustive and --case-alias-strategy exhaustive
• keep complete redirect files at each generated alias path, so static hosts and IPFS still resolve the incorrectly cased request directly
• remove exact empty Blazor render markers (<!--!-->) from inline style content before CSS parsing
• when cleaned CSS still fails, narrowly repair generated heading selectors h 1 through h 6, accept the repair only when the resulting CSS parses and minifies successfully, and run the existing verification pass
• preserve arbitrary invalid CSS without guessing

Why

The prior alias implementation generated every combination of independently cased path segments. A route such as /docs/setup/path1 produced variants such as /DOCS/SETUP/PATH1, creating exponential output growth without materially improving the default fallback behavior. The new default covers one incorrectly cased segment at a time, while exhaustive behavior remains available for callers that truly need every combination.

Blazor can emit empty render markers inside serialized <style> content and can split generated heading selectors such as h1 into h 1 around Razor-rendered markup. These are renderer artifacts rather than intentional application CSS. Snapshot now handles only those known forms, validates the repaired stylesheet, and otherwise falls back safely.

User impact

Normal CLI builds now create substantially fewer case-alias redirect files for nested routes. Existing users who require the old behavior can run:

snapshot build <source> --case-alias-strategy exhaustive

Inline CSS generated by the observed Blazor MarkupString pattern should minify without producing the previous fallback diagnostic.

Validation

Added protocol tests for lean versus exhaustive alias generation and processing tests for:

• exact Blazor marker removal
• safe h 1 to h1 repair after parse failure
• refusal to guess-repair unrelated invalid selectors