readseek 0.8.21

readseek:
- vision: evaluate spatial reduction quality (Jarkko Sakkinen)
- vision: pick best of 3 perfect matchings in MergeHalf (Jarkko Sakkinen)
- release: run npm install after version bump (Jarkko Sakkinen)
- release: update npm package integrity metadata (Jarkko Sakkinen)

pi-readseek:
- release: update npm package integrity metadata (Jarkko Sakkinen)

opencode-readseek:
- release: update npm package integrity metadata (Jarkko Sakkinen)

claude-readseek:
- release: update npm package integrity metadata (Jarkko Sakkinen)

readseek.vim:
- Merged readseek.vim into this repository.

Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@iki.fi>