Normalize leading ./ on within-collection relative links (drop per CONTRIBUTING)

[miharp]

Summary

Within-collection relative links across the docs use a leading ./ (e.g. [x](./page.html)), but CONTRIBUTING.md prefers the bare form:

Prefer page.html over ./page.html — the leading ./ is unnecessary.

This tracks a one-time normalization sweep to drop the leading ./ from within-collection relative links, repo-wide.

Scope

~1,960 occurrences across ~251 files:

Collection	./ links	files
_openvox_8x	1,458	146
_openvoxdb_8x	295	53
_openvox-server_8x	149	37
_openbolt_5x	20	12
_openfact_5x	10	3

Notes

• Mechanical — [text](./page.html) → [text](page.html) and [ref]: ./page.html → [ref]: page.html. The ./ resolves identically, so no link behavior changes; this is style-only.
• Don't touch cross-collection absolute links (/openvox-server/latest/…) or external URLs.
• Large diff — probably best as its own PR (or a few, split by collection) so review is manageable, kept separate from content/link-fix work.
• Add a guard so it doesn't creep back: there's no stock markdownlint rule for this, so a small CI step (e.g. grep -rE '\]\(\./|\]: \./' docs/ failing the build) or a custom markdownlint rule would keep new ./ links out.

Context: this normalization has been deferred a few times (e.g. on #265 and during the #262 workstream-E review on #273), where we chose to match each file's existing ./ style rather than mix conventions. This issue is the home for doing it everywhere at once.