Add spork strategy: tooling and documentation

Spork-create mise task sets up a floating-branch soft-fork of a
mirrored upstream project with daily mirror-sync via Forgejo Actions.
Includes explanation card, how-to guides for setup and branch
management, and the spork-create uv script.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

docs/explanation/spork-strategy.md

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+---
+title: Spork Strategy
+modified: 2026-03-28
+last-reviewed: 2026-03-28
+tags:
+  - explanation
+  - git
+  - forgejo
+---
+
+# Spork Strategy
+
+> **Note:** This article was drafted by AI and reviewed by Erich. I plan to rewrite all explanatory content in my own words - these serve as placeholders to establish the documentation structure.
+
+A "spork" is a floating-branch soft-fork strategy for maintaining local changes against upstream projects without creating a true fork. The name: a fork that's trying its hardest not to be one.
+
+## The problem
+
+We mirror upstream projects on forge for supply-chain control. Sometimes we need to carry local patches — workflow support, build tooling, bug fixes. A real fork diverges silently until merge day becomes a nightmare. A spork stays perpetually close to upstream with patches "floating" on top, rebased daily.
+
+## The trade-off
+
+A spork chooses "small frequent pain" (constant rebasing, shifting branch targets) over "rare catastrophic pain" (fork divergence). For a solo operator carrying a handful of patches, this is the right trade-off. The key property: `git log main..blumeops` always shows your complete delta from upstream. No mystery divergence.
+
+Long-lived work against a sporked repo must accept that there is no "safe" branch — everything is an ever-shifting target. Anyone with a local checkout needs to be comfortable with `git pull --rebase`.
+
+## Architecture
+
+Three remotes, five branch types, one daily sync workflow. The `blumeops` branch is the default — it looks just like upstream with local workflows overlaid. Feature branches come in two flavors: upstreamable (branched off `main`, clean for contribution) and non-upstreamable (branched off `blumeops`, local-only). A `deploy` branch merges everything together as a build artifact.
+
+Forgejo Actions only checks `.forgejo/workflows/` when that directory exists, so upstream's `.github/workflows/` won't run on forge — no deletion needed. If upstream has its own `.forgejo/` directory (rare), it's removed during spork setup.
+
+## How-to guides
+
+- [[create-a-spork]] — initial setup with `mise run spork-create`
+- [[manage-spork-branches]] — feature branches, the deploy branch, handling rebase conflicts
+
+## See also
+
+- [[manage-forgejo-mirrors]] — how upstream mirrors work
+- [[kingfisher]] — first project using the spork strategy