Adds seed/ directory with:
- AGENTS.md: zot operational rules (mother, verbs, capabilities)
- harness.toml: harness="zot", model="deepseek-v4-pro"
- env.placeholder: template for API key injection
build.sh seed population step reads provider keys from the build host's
/usr/local/etc/colibri/provider.env and writes them to the seed partition's
env file. Also installs AGENTS.md, harness.toml, and the layered-soul backup.
Keys are NEVER committed — only placeholders. Real keys are injected at build
time from the build host's provider.env (DEEPSEEK_API_KEY, OPENROUTER_API_KEY).