Negation entry with a constrained placeholder silently disables the entire convention

Bug: a paths negation with a constrained placeholder silently disables the entire convention

Versions: reproduced on konsistent@1.0.0-beta.3 and 1.0.0-beta.4 (Node 26, macOS).

Repro

repro/
  package.json                 # {"name":"repro","private":true}
  konsistent.json
  packages/good/{package.json,tsconfig.json,src/index.ts,test/}
  packages/temporal/{package.json,tsconfig.json,src/activities.ts,test/}   # NOTE: no src/index.ts
  packages/excluded-pkg/package.json

{
  "version": "v1",
  "conventions": [
    {
      "name": "shell",
      "paths": ["packages/{packageName}", "!packages/{packageName:matches(^(excluded-pkg)$)}"],
      "must": { "haveType": "directory", "haveFiles": ["src/index.ts"] }
    }
  ]
}

konsistent check --format=json → [], exit 0. The convention matches nothing: packages/temporal (missing src/index.ts) is not flagged, and neither is packages/excluded-pkg.

Change only the negation to a literal:

"paths": ["packages/{packageName}", "!packages/excluded-pkg"]

→ correctly reports packages/temporal Missing required file: src/index.ts (and skips excluded-pkg), exit 1.

Control without any negation: both temporal and excluded-pkg are flagged, as expected.

Expected

A negation entry with an inline constraint (!packages/{p:matches(^(a|b)$)}) should exclude only the paths whose captured value satisfies the constraint — per docs/reference/path-patterns.md#negation + constraints.md, constraints "skip" non-matching captures, so the negation should apply to a/b only.

Actual

The presence of a constrained-placeholder negation entry appears to negate every path the positive pattern matched (or fails to match and swallows the set) — the convention becomes a silent no-op. konsistent validate reports the config as valid, so nothing surfaces the dead rule.

Why this is nasty

Our production config used exactly this shape ("!packages/{packageName:matches(^(blob|extract|monitor)$)}") and our main structural convention was a no-op for weeks while check printed green. Suggest: either fix constraint evaluation in negation entries, or reject constrained placeholders in negations at validate time.

Start by reproducing the issue with the provided konsistent.json and run konsistent check --format=json, then compare constrained and literal negation behavior. Read docs/reference/path-patterns.md#negation and constraints.md for the intended semantics. Done means constrained negations exclude only matching captures, nonmatching paths are still checked, and validation does not accept a silently dead convention.