Fix inline comment marker scanning

[sedge-bot]

Summary

• Fixes marker scanning for shell-style trailing comments like alias ls='...' # >> note
• Extracts the marker scanner into a small testable core module
• Adds a Node-based regression test for inline shell comments and non-comment strings/URLs

Test Plan

• Observed RED first: npm test --prefix packages/vscode-extension failed because markerScanCore did not exist
• npm install --prefix packages/vscode-extension --legacy-peer-deps for local toolchain only; reverted incidental package-lock version churn
• npm test --prefix packages/vscode-extension
• npm run compile --prefix packages/vscode-extension
• git diff --check

Closes #5

[sedge-bot]

Local verification rerun from the Sedge workspace at 2026-05-14 17:33 CDT for head f8fa14b:

• git fetch github main --prune
• npm test --prefix packages/vscode-extension — passed (marker-scan-core tests passed)
• npm run compile --prefix packages/vscode-extension — passed
• git diff --check github/main..HEAD — passed

gh pr checks still reports no checks on the branch, and GitHub marks the PR OPEN / MERGEABLE with mergeStateStatus=UNSTABLE; I don't see a local code/build blocker.

[sedge-bot]

Sedge heartbeat re-verification for head f8fa14b:

• npm test --prefix packages/vscode-extension passed (compile + marker-scan-core tests).
• python3 tools/build.py passed and regenerated the theme/site artifacts cleanly.
• python3 -m py_compile tools/build.py tools/lib/*.py passed.
• git diff --check github/main..HEAD passed.
• Local clone is clean after verification.

GitHub still reports the PR as OPEN / MERGEABLE / UNSTABLE, but I did not find a local code/test failure in the PR-scoped gates.

[sedge-bot]

Heartbeat re-verification at head f8fa14b (PR still OPEN / MERGEABLE / UNSTABLE, with no status checks surfaced by GitHub):

• gh pr view 10 --json state,mergeable,mergeStateStatus,headRefOid,statusCheckRollup confirms the same head and empty check rollup.
• Diff scope remains VS Code extension marker scanning only: packages/vscode-extension/package.json, src/extension.ts, src/markerScanCore.ts, and test/marker-scan-core.test.js.
• Local verification passed: npm install --prefix packages/vscode-extension; npm test --prefix packages/vscode-extension (compile + marker-scan-core tests); python3 -m py_compile tools/build.py tools/lib/*.py; python3 tools/build.py; git diff --check github/main..HEAD.
• Cleaned verifier-only package-lock churn from npm install; clone is clean afterward.

No local code/test blocker found; GitHub's UNSTABLE state still appears to be lack of surfaced checks rather than a failing gate.