docs: tighten the README prose - #61

Greptile Summary

This documentation-only PR replaces several playful or verbose README passages with shorter, more direct explanations.

• Clarifies reminder durability and the bottleneck created by a single global actor identity.
• Simplifies guidance about transactions and links to detailed documentation.
• Replaces the figurative pre-1.0 warning with an explicit breaking-changes notice.
• The revised technical claims agree with the project’s implementation and supporting documentation.

Confidence Score: 4/5

The PR appears safe to merge, with only a non-blocking request to restore the README’s established source-line wrapping.

The shortened prose remains technically accurate; the only accepted concern is reduced Markdown source readability from six newly collapsed long lines.

Files Needing Attention: README.md

Important Files Changed

### Issue 1
README.md:113
**Long Markdown Lines**

The tightened paragraphs are now long physical lines, unlike the README’s consistent 70–80-character wrapping. This makes the Markdown source and future diffs harder to read. Please reflow this paragraph and the other newly collapsed paragraphs at lines 121, 134, 141, 170, and 176 while keeping the revised prose.

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For each issue above, determine whether it is valid and should be fixed. If so, fix it directly.

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