Harness config 1.0.0-alpha.8

1.0.0-alpha.8 adds external target parents and wildcard path expansion for
worktree-oriented projection while keeping configured source roots observable
inside the repository.

External And Wildcard Targets

• Adds optional [[targets]].parent so a target can be projected under an
  external output parent such as a sibling Git worktree while resources, dir
  sources, profiles, ignore rules, and mutable declarations stay anchored in
  the repository.
• Allows [[resources]].path, [[dir]].path, and [[targets]].parent to use
  gitignore-style path patterns, including *, ?, **, character classes,
  and backslash escapes.
• Keeps [[targets]].path static and explicit so activation can create the
  target folder under each resolved parent; wildcard target paths are rejected.
• Expands wildcard source roots and target parents only to existing real
  directories, skips symlinked directories, and treats no-match target parent
  patterns as producing no concrete targets.

Projection, CLI, And Docs

• Preserves target-derived override selection from path, not parent, so
  multiple worktrees using the same target path share the same logical override
  namespace while remaining physically isolated.
• Keeps target-output .harnessIgnore and .harnessProfile controls isolated
  per concrete expanded target.
• Updates harnessc activate, validate, and explain to report and reason
  over concrete expanded target roots.
• Documents the new standard, tooling, conformance, diagnostics, README, and
  website-ready spec behavior, with regression coverage for wildcard matching,
  overlap diagnostics, profiles, ignores, dir merging, and CLI explain output.