Define what a product vision is before stating ORE Studio's

The * Vision section of doc/identity/product_identity.org opens directly with ORE Studio's specific vision statement, with no preamble explaining what a product vision is as a concept. A short introductory paragraph — defining what a product vision is, why projects have one, and what role it plays in deciding what goes into the backlog — should precede the project-specific content. The MASD methodology document (https://mcraveiro.github.io/dogen/docs/the_masd_methodology.html) covers vision and mission as first-class concepts; the relevant text should be reviewed and, where appropriate, adapted or quoted directly so we are not reinventing the wheel.

Readers unfamiliar with the term encounter the heading * Vision and then immediately the ORE Studio statement, with no explanation of what that heading means or why it exists. Adding a brief conceptual definition makes the document self-contained, consistent with the Zettelkasten principle that each node should make sense in isolation, and aligned with how the MASD methodology treats these concepts.

• doc/identity/product_identity.org — the file to update, specifically the * Vision section (line 25 onwards).
• https://mcraveiro.github.io/dogen/docs/the_masd_methodology.html — MASD methodology doc covering vision/mission; check for reusable text.
• Stallworth Williams, Linda (2008). The mission statement: A corporate reporting tool with a past, present, and future. Sage Publications, Los Angeles, CA.

• Product Identity — the document to be updated.
• Document type: product_identity — contract for the product_identity doc type.