Non-interactive prompt values: --set / --set-env

[trick77]

Summary

• Adds --set NAME=VALUE and --set-env NAME=ENV_VAR to opencode-presets install so presets with @prompt directives can be driven non-interactively. Scope across multi-module installs with --set <preset>.NAME=VALUE.
• Documents the quoting gotcha in README — values with $, !, *, etc. must be single-quoted or the shell expands them before the CLI sees the value. --set-env is recommended for secrets so tokens don't land in shell history or process listings.
• Drive-by fix: expandPromptsInValue / expandCacheInValue now substitute object keys too. Before this, mcp-http with a custom header name wrote the literal "{{prompt:headerName}}" as the JSON key — broken for the headline use case.

Test plan

• npm test (73 tests pass, including new cli-args and distribute-set-values suites)
• Manual smoke against a throwaway OPENCODE_CONFIG: happy path with all four --set flags
• --set-env reads from env, value with $ preserved verbatim
• --set typo=x → clean error, exit 1
• --set-env headerValue=UNSET_VAR → clean error, exit 1
• Empty --set name= rejected by the same "cannot be empty" path as interactive
• Header key substitution now produces {"X-Bitbucket-Token": "<token>"} instead of {"{{prompt:headerName}}": ...}

Example

opencode-presets install mcp-http \
  --set name=openrag \
  --set url=https://openrag.example.internal/mcp \
  --set headerName=X-Bitbucket-Token \
  --set-env headerValue=BITBUCKET_TOKEN