Harness config 1.0.0-alpha.4

1.0.0-alpha.4 completes the v1 ignore precedence model, tightens activation
explainability, and updates adoption guidance before the v1 proposal is treated
as final.

Ignore And Projection Semantics

• Defines .harnessIgnore precedence by logical location and logical directory
  depth, with last matching participating rule winning.
• Lets deeper source-local and profile-local ignore files refine or re-include
  paths ignored by shallower rules.
• Evaluates profile-local ignore files at their logical overlay location and
  target-derived override ignore files at their logical source/target
  locations.
• Keeps target-output .harnessIgnore files as the final boundary that cannot
  be undone by repo, source, or profile rules.
• Keeps Harness declaration files out of projection, including
  .harnessIgnore, .harnessProfile, and .harnessProfileRoot.

Tooling And Safety

• Expands harnessc explain --json so ignored, re-included, profile-selected,
  and target-output-filtered paths report the winning rule consistently.
• Adds explicit target symlink policy: target symlinks conflict by default and
  are replaced only when the manifest or CLI explicitly selects replacement.
• Adds coverage for resource-root ignores, profile selection across resource
  groups, target-derived override ignores, target-output final boundaries,
  synthetic declaration ignores, and idempotent activation.

Adoption Guidance

• Updates the public Harness config skill and references with the v1 adoption
  model: resources-first, meaningful resource groups, first-class
  .harness/local/, scoped nested ignores, profiles as modes, and tracked
  bootstrap for gitignored generated surfaces.
• Clarifies that AGENTS.md, CLAUDE.md, and similar root files can stay as
  normal tracked files unless [[dir]], composition, profiles, or local
  overlays make generation useful.
• Documents npx skills / skills.sh workflows, skills-lock.json provenance,
  and promotion of reviewed skills into .harness source.
• During the v1 alpha, release automation continues publishing the current
  alpha on the npm latest dist-tag so default npx harnessc resolves to the
  current proposal.