fix(#705): route hardcoded $HOME gsd-tools invocations in agents/commands through gsd_run (#707)

* fix(#705): route hardcoded $HOME gsd-tools invocations in agents/commands through gsd_run

The hardcoded `node "$HOME/.claude/gsd-core/bin/gsd-tools.cjs" <cmd>` form
(fixed for workflows in #621/#637) survived in agent/command surfaces and
misresolves on global/shim-only installs. Route every agent-executed
invocation through the resolved `gsd_run` launcher in gsd-phase-researcher,
gsd-planner (load_graph_context extracted to a shared reference to stay under
the planner size budget), import, and graphify. Add a regression guard over
agents/ + commands/ + gsd-core/references/ bash blocks. User-facing display
messages and docs are intentionally left untouched.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

* fix(#705): use repo changeset fragment format (type: Fixed, pr: 707)

The hand-written fragment used the standard changesets package format
(package: bump) which lacks the type:/pr: frontmatter the repo's
docs-required lint consumes (fail_malformed_fragment / missing_type).
Regenerated via scripts/changeset/new.cjs.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 4.8 <noreply@anthropic.com>

tests/graphify-visualization.test.cjs

@@ -469,8 +469,8 @@ describe('regressions', () => {
       'a bash code block must invoke `graphify update .`'
     );
     assert.ok(
-      bashBlocks.some(b => /gsd-tools\.cjs["']?\s+graphify build snapshot/.test(b.content)),
-      'a bash code block must invoke `gsd-tools.cjs graphify build snapshot`'
+      bashBlocks.some(b => /gsd_run\s+graphify build snapshot/.test(b.content)),
+      'a bash code block must invoke `gsd_run graphify build snapshot`'
     );
   });