📝 docs(plan): p9-fb-27 implementation plan
17-task TDD plan covering: typed signal scaffolding (kebab-app
error_signal module), ConfigInvalid + NotIndexed typed errors, SchemaV1
struct + schema_with_config facade, count_summary helper, wire_schema +
wire_error_v1 helpers, error_classify dispatcher, Cmd::Schema CLI arm,
--json mode error.v1 emission, JSON Schema literals, doc sync.
Each task = bite-sized TDD cycle (write failing test → impl → verify
pass → commit). Final task = workspace clippy + cargo test --workspace
-j 1 + manual smoke.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
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