fix(opencode): drop mcp shrink auto-registration and fix tools schema

[alaa-alghazouli]

• Stop registering broken standalone caveman-shrink mcp. Emit wrap instructions instead.
• Convert agents/cavecrew-*.md tools array to opencode object schema.
• Add missing caveman-compress.md command file to fix installer tests.

CI will resync plugins/caveman/agents/... on merge.

[gitPhate]

@alaa-alghazouli thank you for this PR as it saved me a lot of headaches; I installed caveman for OpenCode on windows via powershell (solution to the .ps1 script not working: here) but I also had to manually move all the installed files from C:\Users\<username>\AppData\Roaming\opencode\ to C:\Users\<username>\.config\opencode\ according to the opencode docs, you might want to fix this as well in your PR.

[de-flandres]

Is there any quick manual fix?

[alaa-alghazouli]

@alaa-alghazouli thank you for this PR as it saved me a lot of headaches; I installed caveman for OpenCode on windows via powershell (solution to the .ps1 script not working: here) but I also had to manually move all the installed files from C:\Users\<username>\AppData\Roaming\opencode\ to C:\Users\<username>\.config\opencode\ according to the opencode docs, you might want to fix this as well in your PR.

Hey @gitPhate, glad my PR saved you some headaches! Just pushed a fix for the Windows path issue too, opencodeConfigDir() now always uses ~/.config/opencode so no manual file moving needed anymore

[gitPhate]

@alaa-alghazouli great work, many thanks!
@de-flandres the fix is to manually apply the content of this PR