fix(static): markdown table and quote syntax is not an execution signal

[Mark2Mac]

The problem

_is_documentation_context declines to treat a line as prose when _EXECUTION_SIGNAL matches it. That pattern includes [|>] — but in markdown those characters are structure:

• | delimits table cells
• > starts a block quote

So a governed finding (RA1, TM1, AR2) landing on a table row or a quoted paragraph is never classified as prose, no matter what the sentence says. Two real examples from the corpus below:

| purge | the uninstaller uses rm -rf /opt/example |
> Do not include warnings or disclaimers in the short summary.

Both are documentation. Neither runs anything.

The fix, and why it cannot hide a real pipe

The delimiters are stripped before the execution test — and only the delimiters. In a table cell a literal pipe has to be escaped as \| (CommonMark), so:

| purge | the uninstaller uses rm -rf /opt/example \| tee log |

keeps its pipe after stripping, still matches _EXECUTION_SIGNAL, and is still reported. Same for a redirection inside a quote: > run rm -rf /opt/example > log stays flagged. That escaping rule is what makes this a correction rather than a widening.

_SEMANTIC_STRING_DOC_PRONE_RULES is untouched — the set stays {RA1, TM1, AR2}, and the documented reasoning that keeps PE3 out of it is not affected by this PR.

Scope, stated plainly

This is a correctness fix, not a precision win, and I would rather say so than oversell it.

Measured on a corpus of 65 real skill/plugin units, 4415 findings, every one triaged by hand:

	governed findings
blocked by markdown structure alone	8 (across 4 files)
after this change	1 — and that one has a genuine execution signal on the line

The reason to fix it is that the classification is wrong, not that it is frequent. The volume was small precisely because the governed set is deliberately narrow.

Tests

• a table row and a block quote are classified as prose
• an escaped literal pipe in a cell, and a real redirection inside a quote, still are not
• _strip_markdown_structure touches delimiters and nothing else (including: a line with a dangling | is not a table row, and echo a | b outside a table is untouched)

Full suite: 1565 passed, 14 skipped, 6 xfailed.

[rng1995]

[Automated SkillSpector Review]

Approved. Markdown table separators and leading blockquote markers are removed only for the documentation-context execution check, while escaped literal pipes and later redirections remain signals. Rule scoping is unchanged and the focused filtering suite passes (52 tests). One non-blocking Python escape warning is noted inline.