docs(references): port style guides, 24 diagram guides, and 9 templates from opencode

All content ported from borealBytes/opencode under Apache-2.0 license with
attribution headers prepended to each file.

- references/markdown_style_guide.md (~733 lines): full markdown formatting,
  citation, collapsible sections, emoji, Mermaid integration, and template
  selection guide
- references/mermaid_style_guide.md (~458 lines): full Mermaid standards —
  emoji set, classDef color palette, accessibility (accTitle/accDescr),
  theme neutrality (no %%{init}), and diagram type selection table
- references/diagrams/ (24 files): per-type exemplars, tips, and templates
  for all Mermaid diagram types
- templates/ (9 files): PR, issue, kanban, ADR, presentation, how-to,
  status report, research paper, project docs

Source: https://github.com/borealBytes/opencode

scientific-skills/markdown-mermaid-writing/references/diagrams/git_graph.md

@@ -0,0 +1,74 @@
+<!-- Source: https://github.com/borealBytes/opencode | License: Apache-2.0 | Author: Clayton Young / Superior Byte Works, LLC (Boreal Bytes) -->
+
+# Git Graph
+
+> **Back to [Style Guide](../mermaid_style_guide.md)** — Read the style guide first for emoji, color, and accessibility rules.
+
+**Syntax keyword:** `gitGraph`
+**Best for:** Branching strategies, merge workflows, release processes, git-flow visualization
+**When NOT to use:** General processes (use [Flowchart](flowchart.md)), project timelines (use [Gantt](gantt.md))
+
+---
+
+## Exemplar Diagram
+
+```mermaid
+gitGraph
+    accTitle: Trunk-Based Development Workflow
+    accDescr: Git history showing short-lived feature branches merging into main with release tags demonstrating trunk-based development
+
+    commit id: "init"
+    commit id: "setup CI"
+
+    branch feature/auth
+    checkout feature/auth
+    commit id: "add login"
+    commit id: "add tests"
+
+    checkout main
+    merge feature/auth id: "merge auth" tag: "v1.0"
+
+    commit id: "update deps"
+
+    branch feature/dashboard
+    checkout feature/dashboard
+    commit id: "add charts"
+    commit id: "add filters"
+
+    checkout main
+    merge feature/dashboard id: "merge dash"
+
+    commit id: "perf fixes" tag: "v1.1"
+```
+
+---
+
+## Tips
+
+- Use descriptive `id:` labels on commits
+- Add `tag:` for release versions
+- Branch names should match your actual convention (`feature/`, `fix/`, `release/`)
+- Show the **ideal** workflow — this is prescriptive, not descriptive
+- Use `type: HIGHLIGHT` on important merge commits
+- Keep to **10–15 commits** maximum for readability
+
+---
+
+## Template
+
+```mermaid
+gitGraph
+    accTitle: Your Title Here
+    accDescr: Describe the branching strategy and merge pattern
+
+    commit id: "initial"
+    commit id: "second commit"
+
+    branch feature/your-feature
+    checkout feature/your-feature
+    commit id: "feature work"
+    commit id: "add tests"
+
+    checkout main
+    merge feature/your-feature id: "merge feature" tag: "v1.0"
+```