Devlog: Syncing Flower’s Docs Back to Reality

Just a doc cleanup lol. No code change or compiler updates. Probably did more than needed for now but oh well!

The mismatch was REALLY bad. The old docs preserve old assumptions, and someone reading them could walk away with a version of Flower that no longer really exists (or, in some cases, doesn’t exist yet or never ever existed)!

What changed

I updated the docs that had drifted the most from reality (relatable):

• README.md now reflects the current type-system shape
• ROADMAP.md treats v1.4 as accomplished
• the v1.4.0 milestone doc now includes more of the outcome, not just the original plan
• contributor docs no longer have stale semantics
• structure.md is more accurate to what Flower currently is, and what still needs a fuller rewrite later

Yea, that’s it.