Tighten naming conventions wording

[JeroenDeDauw]

Follows-up to #1295, which merged before the text pass ran. Prose only; no rule changes what it permits or forbids.

• The "store" section's closing sentence restated its opening instruction and justified it. Its one piece of new content, the scope (identifiers, docs, discussion), moves into the instruction; the justification goes.
• The third "store" bullet gets the bold lead-in the other two have. only is retained, so the restriction is unchanged.
• ## Known collisions, unresolved becomes ## Known unresolved collisions, the phrasing Add code-facing naming conventions doc #1295's own description uses. Nothing in either repo links to the page or its anchors.

Considered, omitted: <X>Picker is defined twice, under "Data access and selection" and again under "Vue component suffixes". Kept, because the first is what makes the Lookup/Picker collision rule below it actionable.

The pass also checked every identifier the page names against the code. Two of its claims did not hold at #1295's merge commit, and both are already answered elsewhere: SubjectLookup named both a read port and a Vue selection widget, which #1296 has since renamed; and "Graph Store" is cited as a Glossary term the glossary does not yet define, which #1294 adds. Neither needs a change here.

_{AI-authored — Claude Code, Opus 5 (max); delegated text-review pass on #1295 for @JeroenDeDauw, no redirection; diff not yet human-reviewed; verified the changed rules are meaning-invariant, that no inbound link targets the renamed heading, and checked every identifier the page names against the code.}