Report Go module version in direct installs

[joerucci]

What changed

• fall back to the Go module build version when no GoReleaser linker version is present
• keep GoReleaser and CI linker-injected versions authoritative
• normalize Go module versions from v3.0.0 to the CLI's existing 3.0.0 display format
• add focused coverage for linker, module, and local-development version resolution

Why

Verification of v3.0.0-rc.1 found that the official npm and GitHub binaries correctly reported 3.0.0-rc.1, but a direct go install github.com/ghostable-dev/ghostable/v3/cmd/ghostable@v3.0.0-rc.1 build reported dev because it does not use the GoReleaser linker flags.

This keeps direct Go installs accurate without changing the signed release pipeline.

Validation

• focused version-resolution tests
• make check
• make security-check
• linker-injected version smoke test
• local development fallback smoke test
• git diff --check

The published v3.0.0-rc.1 tag is not modified or reused. After this merges, the behavior can be verified with a new prerelease such as v3.0.0-rc.2.