[fix] Embed CAPL version in ko images

[komer3]

What this PR does / why we need it:

Fixes the ko build targets so release images receive CAPL's linker-injected version instead of starting as dev. It also corrects the malformed local ko cache assignment.

Which issue(s) this PR fixes:

Special notes for your reviewer:

Built a local ko image with VERSION=v0.10.0 and verified its startup log reports CAPL version: v0.10.0.

TODOs:

• includes documentation (not needed; no user-facing contract changes)
• adds unit tests (not needed; tested the built image)
• adds or updates e2e tests (not needed; build-time version injection only)

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 70.14%. Comparing base (4c9eb88) to head (13796ec).

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #1135   +/-   ##
=======================================
  Coverage   70.14%   70.14%           
=======================================
  Files          71       71           
  Lines        6720     6720           
=======================================
  Hits         4714     4714           
  Misses       1715     1715           
  Partials      291      291           

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