fix(cli): #1713 decode url-encoded dynamic route params from getparamsfromsegment

[jstockdi]

Related Issue

Resolves #1713

Documentation

N/A — no user-facing documentation change. This restores the already-documented behavior that dynamic route params round-trip losslessly from getStaticPaths to getBody / getStaticParams.

Summary of Changes

1. getParamsFromSegment (packages/cli/src/lib/url-utils.js) now decodeURIComponents each URLPattern group value, mirroring the decode already applied to ids/labels/titles in lifecycles/graph.js. Decoding is guarded with try/catch so a malformed value falls back to its raw form, and undefined catch-all group values are passed through untouched.
2. This makes non-ASCII / spaced slugs (e.g. café, hello world) reach getBody decoded, and fixes the execute-route-module.js param comparison (both sides are now decoded), so getStaticParams pages no longer crash the build.
3. Added regression test packages/cli/test/cases/build.default.dynamic-params-encoded/: a [slug].js whose getStaticPaths returns café and whose getBody echoes params.slug; asserts the built page contains the decoded café, not caf%C3%A9. Verified failing on unpatched source and passing with the fix.
4. No breaking changes. Output file/directory paths are unaffected (they derive from the already-decoded getStaticPaths params). Existing dynamic-routing / getStaticPaths / SSR / API-route specs continue to pass.