docs(provenance): migrate the corpus to the Research registry grammar

Repoint every `Research doc:` at the plugin's Research registry
(git/sources.md, pre-commit/sources.md, gitea/sources.md,
agentsmd/sources.md), keeping the old topic-doc link as a parenthetical
`(digest: ...)` annotation. Brace expansions and the gitea-releases
semicolon pair collapse to one path.

Entries with no registry (org-commit-conventions, org-git-conventions,
governance-secrets-hard-prohibition, adr-0002-0003-two-tier-claude-md)
now declare `none` plus `Basis:` bullets. The two git entries cite
core/instructions/git.md and commits.md as `(removed in 5deed07)`.

Remove the house-vale-3-15-2-repro entry and its source_keys citations
from vale-config and vale-run. It claimed six behaviours were reproduced
against purpose-built fixtures in this repo, but the entry was added in
d1afdbe with no test or fixture files, and none exists in history. The
behavioural rules stay; only the unbacked provenance claim goes.

Refs: #121
ADR: 0028
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01EGHFJextYtVQseaHPDDhxB

plugins/git/.apm/skills/git-history/references/sources.md

@@ -10,7 +10,7 @@ source_keys:
 
 Git bisect documentation covering binary search through commit history to find the commit that introduced a bug. Includes manual flow, automated mode with exit codes, skip patterns, and visualization options.
 
-- **Research doc:** plugins/git/docs/research/docs/git/history-inspection.md
+- **Research doc:** plugins/git/docs/research/docs/git/sources.md (digest: plugins/git/docs/research/docs/git/history-inspection.md)
 - **Doc heading:** `## git bisect`
 - **Contributing files:** SKILL.md, references/bisect.md
 
@@ -18,7 +18,7 @@ Git bisect documentation covering binary search through commit history to find t
 
 Git log documentation covering format presets, custom format placeholders (commit identity, author, committer, message, refs, GPG signature), pickaxe search (`-S` and `-G`), `--follow` for file renames, `--diff-filter`, and line-range history (`-L`).
 
-- **Research doc:** plugins/git/docs/research/docs/git/history-inspection.md
+- **Research doc:** plugins/git/docs/research/docs/git/sources.md (digest: plugins/git/docs/research/docs/git/history-inspection.md)
 - **Doc heading:** `## git log — Format and Filtering`
 - **Contributing files:** SKILL.md, references/git-log-format.md
 
@@ -26,6 +26,6 @@ Git log documentation covering format presets, custom format placeholders (commi
 
 Git diff documentation covering output control (--stat, --name-only, --name-status, --word-diff) and whitespace handling flags.
 
-- **Research doc:** plugins/git/docs/research/docs/git/history-inspection.md
+- **Research doc:** plugins/git/docs/research/docs/git/sources.md (digest: plugins/git/docs/research/docs/git/history-inspection.md)
 - **Doc heading:** `## git diff — Output Control`
 - **Contributing files:** SKILL.md, references/git-log-format.md