Migrate external commands to Zod

[waldekmastykarz]

Summary

Migrates all external commands from the legacy options/validators/telemetry pattern to Zod schema validation.

Closes #7302

Changes

Migrated the following commands:

• connection-add — ID validation (length, alphanumeric, reserved words) via .min()/.max()/.refine()
• connection-get — Option set (id/name) via getRefinedSchema()
• connection-remove — Option set (id/name) + force boolean via getRefinedSchema()
• connection-doctor — ux enum validation via z.enum()
• connection-schema-add — External connection ID + JSON schema content validation via .refine()
• connection-urltoitemresolver-add — Simple required options migration
• item-add — ACL validation via .refine(), uses z.object (not z.strictObject) for allowUnknownOptions support, switched to addUnknownOptionsToPayloadZod

connection-list was already migrated to Zod.

Testing

• All 15724 tests pass
• Lint passes
• 100% coverage on all changed files