docs: replace hyphen-as-dash prose with natural sentences

[joshua-temple]

Problem

Several docs pages used a hyphen as a sentence-level dash or parenthetical break (the - X - and trailing - clause constructions), which reads as an unnatural writing tic.

Fix

Copyedited the affected prose into natural sentences: split into two sentences, or used a comma or colon where that was the cleanest option. Scope was prose only.

Preserved everywhere: compound-modifier hyphens (platform-enforced, fail-closed, multi-env, etc.), Markdown list-item markers, table structure and empty-value cells, code spans, inline flags, URLs, file paths, and version strings. The repo's no-em-dash rule was respected; no em/en dashes were introduced.

Verification

• 8 files changed, 30 dash-constructions rewritten.
• Frontmatter intact and code fences balanced on every edited page.
• Docs site build not run (local Node is v20; Starlight needs >=22); markdown validated structurally instead.