docs: simplify README to problem→solution with new hero images

Cut 712 → 93 lines: keep only the problem, the solution, install, verify,
and pointers to docs/. Drop tier tables, env-var matrix, perf section,
MCP register block, FAQ, alternatives, dead-ends, schema.org block, and
agent contract surface — they all live in docs/ already.

Refresh headline latency: ~15 ms (Tier 3 daemon) / ~120 ms (bash fallback),
matching what the trigger log actually measures.

Replace the SVG hero with two Higgsfield-generated PNGs:
- assets/hero-problem-solution.png — before/after split
- assets/paste-closeup.png — PrtScr → image-in-chat close-up

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: NagyVikt