refactor: remove 'version.Get()' and only use 'version.Raw()'

[mwbrooks]

Changelog

• N/A

Summary

This pull request removes version.Get() and only uses version.Raw(). The motivation is the simplify version handling to be 1 method instead of 2 methods.

Context:

PR #429 consolidated version handling to prefer version.Raw() and slackcontext.Version(ctx). A follow-up task was to remove version.Get() entirely since it creates confusion about which function to use. The only difference is that .Get() prepends a v prefix if missing - but we can guarantee the v prefix is always present without requiring .Get().

Why it's Safe to Remove:

The v prefix is already guaranteed in all code paths that set Version:

1. Build-Time (Makefile): git describe --tags --match 'v*.*.*' - the --match pattern requires a v-prefixed tag, and git describe outputs the matching tag name, so the result always starts with v.
2. Default Value (version.go): "v0.0.0-dev" - already has the prefix.
3. Env Var Override (version.go): SLACK_TEST_VERSION - this is the one gap. QA testers could set it without a v. This PR adds validation by moving the v-prefix enforcement from .Get() into init(), ensuring Version is normalized at startup.

Open Question 🧠

• Do we want to rename version.Raw() to version.Version()?
  • Technically, it's no longer the "raw" version because it may have a v-prefix added.
  • In the future, we may want a version.Major(), version.Minor(), etc to get specific elements of the version.

Requirements

• I've read and understood the Contributing Guidelines and have done my best effort to follow them.
• I've read and agree to the Code of Conduct.

[codecov]

Codecov Report

❌ Patch coverage is 53.84615% with 6 lines in your changes missing coverage. Please review.
✅ Project coverage is 70.35%. Comparing base (0c37128) to head (e114959).

Files with missing lines	Patch %	Lines
internal/pkg/auth/login.go	0.00%	3 Missing ⚠️
cmd/root.go	33.33%	2 Missing ⚠️
cmd/upgrade/upgrade.go	0.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #445      +/-   ##
==========================================
+ Coverage   70.32%   70.35%   +0.02%     
==========================================
  Files         220      220              
  Lines       18506    18506              
==========================================
+ Hits        13015    13020       +5     
+ Misses       4313     4311       -2     
+ Partials     1178     1175       -3     

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[mwbrooks]

A few notes for the semantic minded versioners 🔢

[mwbrooks]

note: We now enforce the v prefix on init() so that all version-pathways will now have a v prefix.