[Manohar Paturi (ManoharPaturi)]

Motivation & Context

_escape_markdown_line prepended one backslash to any line starting with # or \#, but _unescape_markdown_line only stripped a backslash from a body starting with exactly \#. A line that already began with an escaped hash therefore gained a backslash on every write and read cycle, and the corruption compounded across the rereads that auto loading and consolidation perform. Reproduced on main with a one line round trip: \# literal fact came back as \\# literal fact.

Description & Review Guide

• What are the major changes? The escape maps a run of n backslashes before a hash to 2n + 1, and the reader reduces an odd run back to the original n. A plain # line still gets the single backslash it always had, which is the n = 0 case.
• What is the impact of these changes? Every backslash run length round trips exactly. Even runs are not produced by this writer, so the reader passes them through untouched; that also keeps lines written by the previous scheme from being mangled further.
• What do you want reviewers to focus on? The round trip test covers a plain hash line, a single escaped hash, and a two backslash run, and fails on main.

Related Issue

Fixes #9727

AI Assistance

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