docs(profile): dedupe and tighten the bottom half of README

[amavashev]

Cuts the org profile README from 354 → 206 lines (-42%) by collapsing overlapping sections. No content removed in spirit; ~5 sections that all answered the same question are merged into one each.

Why this PR

The bottom half had grown into ~14 sections with substantial overlap. Specifically:

• 5 sections all answered "what IS Runcycles?" ("What is Cycles?" + "What is Runcycles?" + "How it works" + "Quick mental model" + "The ecosystem")
• 4 sections all answered "who is this for?" ("Typical use cases" + "Who Runcycles is for" + "Where Runcycles fits" + "When to use Runcycles")

A first-time visitor doesn't read 354 lines on a profile README — they skim. Cutting the redundancy makes the surviving prose actually land.

What changed

Before	After
"What is Cycles?" + "What is Runcycles?" + "Quick mental model" + "The ecosystem" (4 sections)	Single "What this is" (1 section, 3 paragraphs)
"Typical use cases" + "Who Runcycles is for" + "Where Runcycles fits" + "When to use Runcycles" (4 sections)	Single "Who it's for" (1 section, 3 paragraphs)
"How it works" (15 lines explaining the loop)	4 lines pointing at the diagram + Try-it snippets above
"What Runcycles enforces" with 5 sub-headings	5-bullet list
"Status" (vague)	"Status" + CHANGELOG link (load-bearing)

What was dropped

• Mid-page "👉 Learn more" CTA at the old line 131 — sat before 220 more lines of content, read as a false page-end
• Web3 / EVM / "blockchain transactions" mentions + the defensive "Web3 is one surface area, not a requirement" one-liner. Not active product positioning; reads as holdover
• Broken docs URL (`runcycles.github.io/docs` → fixed to the canonical `runcycles.io`)

What was kept verbatim

• Top half (badges, hook, value-prop bullets, CTA links, architecture diagram, GIF demo, Try-it MCP+Python snippets, Start-here repo list) — untouched
• "Why Runcycles exists" — distinct motivation, kept (slightly compressed from 11 short lines to 2 paragraphs)
• "What Runcycles is not" — orthogonal differentiator, kept verbatim
• "Design principles" — short and load-bearing, kept verbatim

Test plan

• On the PR's Files-changed → View file, confirm rendered output reads cleanly top-to-bottom
• Verify no broken links (the `runcycles.io` and ARCHITECTURE.md links resolve)
• Mobile: confirm no horizontal-scroll issues
• After merge, sanity-check at https://github.com/runcycles