fix(drift): treat pipe-alternation shorthand as not a path

[dyk1454683243-sudo]

What

Treat pipe-alternation shorthand such as `tests/grounding|traversal|edges|store.test.ts` as not a filesystem path, so it never becomes a path claim or MISSING_PATH.

isNotAPath already dropped globs with */? but not |. A token with | separating path segments or basenames is prose shorthand, not a file. Real paths without pipes stay claims: a missing tests/store.test.ts is still MISSING_PATH.

No fancy parser — the issue token is a single inline-code string containing |.

Why

Addresses #202 (bullet 4 only).

Do not treat this as Fixes #202 or Closes #202 — that would auto-close the whole mega-issue.

Remaining #202 bullets stay open:

1. Symbol notation (src/auth/login.validateToken) — owned by fix(drift): treat qualified-name symbol notation as not a path #220
2. Compound extensions (.d.ts) — owned by fix(drift): treat compound extensions like .d.ts as not-paths #216
3. Hypothetical examples (./x, x.ts, x/index.ts) — owned by fix(drift): treat resolution stubs like ./x as not-paths #222
4. Scoped-package resolve (@scope/pkg/package.json vs bare specifier) — owned by fix(drift): resolve scoped packages by bare specifier #217
5. gitignore trailing-slash directory exemption — owned by fix(drift): honor trailing-slash gitignore rules for absent paths #218

Type of change

• Bug fix
• New feature
• Refactor
• Docs
• CI/Tooling

How to test

1. npx vitest run src/drift
2. Confirm markdown that cites `tests/grounding|traversal|edges|store.test.ts` produces zero path claims and zero MISSING_PATH for that token.
3. Confirm a real missing file such as tests/store.test.ts is still reported as MISSING_PATH.
4. Confirm existing MISSING_PATH false positives: negation only heading-scoped, non-path tokens treated as paths, dot-dir glob blind spot #143 cases stay green.
5. npm run typecheck

Checklist

• Focused drift tests pass (npx vitest run src/drift — 11 passed, 1 skipped #201 version-shaped case left untouched)
• Typecheck passes (npm run typecheck)
• Tests pass (npm test) — full suite is not the gate for this one-filter change
• No breaking changes (or documented below)
• Tested locally with a real project

Code-graph changes

• This PR targets main
• A linked issue agrees on the bounded extractor/resolver scope
• The change follows the frozen LanguageExtractor or FrameworkResolver interface
• A focused fixture and assertions for the expected node/edge shape are included
• Any new grammar WASM, extension mapping, extractor, or resolver is registered
• No graph identity, reconciliation, schema, or drift-semantics changes are included, or a core / discuss-first issue is linked above

This is a drift claim-extraction filter only. It does not change graph identity, extractors, or the other #202 bullets. Issue #202 stays open.

[dyk1454683243-sudo]

Withdrawing this PR while I clean up a high-volume open-PR backlog. Sorry for the noise — happy to come back later with a focused change if useful.