docs: trim repeated boilerplate in git, gitea, and bin skills

Finding 13: five blocks of near-identical wording were repeated across
skills within a plugin — the gitea "resolve owner and repo" step (5
skills), the 404-masks-403 note (6 files), the manual pagination
explanation (8 files), the git plugin's main/master force-push refusal
(7 files, some with multiple internal restatements), and the bin
skills' domain-glossary/ADR paragraph (5 skills). Tightened each
instance in place — same meaning, fewer words — rather than extracting
to a shared file, which ADR-0014's one-file-per-skill install
constraint rules out. Left the three git skills' structured-result
JSON shapes alone (coupled to the separate, out-of-scope git-orchestrate
merge candidate, finding 19).

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01YR2CjVumUbEGWcMikcoXBD

plugins/gitea/skills/gitea-issues/references/issues.md

@@ -45,7 +45,7 @@ list_issues owner: <owner> repo: <repo> state: "open" type: "issues"
 `updated_at`, and optionally `labels` (`[]string`), `milestone` (`{id, title}`), `ref`, `deadline`.
 Body and `closed_at` are omitted from list responses — call `issue_read method: "get"` for those.
 
-Paginate with `page`/`per_page` until the returned count is less than `per_page`.
+Paginate: `page`/`per_page`, stop once the count is below `per_page`.
 
 ## `issue_read`