docs(adr-0003): keep Forgejo canonical, complete the GitHub mirror (reject swap)

Grilled the 'swap Forgejo for GitHub' idea. Root cause of the divergence pain
is an incomplete push-mirror rollout (14 repos dual-pushed, push_mirrors=0),
not Forgejo itself — and CONTEXT.md already documents Forgejo-canonical +
one-way GitHub mirror. Decision: don't swap; finish the mirror, name the
GitHub-first exceptions, reconcile infra, enforce one-remote-per-clone. Adds
ADR-0003 + the GitHub-first repo glossary term + dual-push/force-overwrite
warnings on Canonical repo / GitHub mirror.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

CONTEXT.md

@@ -173,13 +173,17 @@ The split where every owned image is built+pushed by GitHub Actions and Woodpeck
 _Avoid_: bare "Woodpecker pipeline" — say "build" or "deploy"; "fallback build" (the in-cluster fallback path was removed by ADR-0002).
 
 **Canonical repo**:
-The Forgejo `viktor/<name>` repo — the only place commits land, workflow files included.
+The Forgejo `viktor/<name>` repo — the only place commits land, workflow files included. Every first-party repo is Forgejo-canonical *except* an explicit set of **GitHub-first repos**. A clone keeps **only** the canonical remote (ADR-0003): the **GitHub mirror** is not a second push target.
-_Avoid_: "upstream" (ambiguous); committing anywhere else.
+_Avoid_: "upstream" (ambiguous); committing anywhere else; keeping both remotes on a clone and hand-pushing to each (the dual-push habit that caused the 2026-06 divergence — ADR-0003).
 
 **GitHub mirror**:
-The GitHub repo a **Canonical repo** push-mirrors to, one-way, so GitHub Actions can build from it; anything committed on the mirror is silently overwritten by the next sync.
+The GitHub repo a **Canonical repo** push-mirrors to, one-way (Forgejo's `push_mirrors`, `sync_on_commit`), so GitHub Actions can build from it; anything committed on the mirror is silently overwritten by the next sync — and enabling the mirror **force-overwrites** the GitHub side, so a diverged GitHub-only commit must be merged back into Forgejo *before* the mirror is turned on or it is lost.
 _Avoid_: treating it as a second writable remote; bare "the GitHub repo" without saying mirror.
 
+**GitHub-first repo**:
+The deliberate exception to the **Canonical repo** rule — a repo whose canonical home is GitHub, so it sits outside the mirror policy. Two kinds: third-party clones/forks where GitHub is genuinely upstream (`jsoncrack.com`, `snmp_exporter`, `SparkyFitness`, `agent-rules-books`, `Plotting-Your-Dream-Book`), and a first-party repo intentionally kept public on GitHub (`health`). Single GitHub remote, never dual-pushed.
+_Avoid_: adding a Forgejo remote "for consistency"; treating one as a **Canonical repo**.
+
 **Forgejo registry**:
 Forgejo's built-in container registry — since ADR-0002 a frozen archive holding one last-known-good tag per **Service**, not a build target; owned images live on ghcr.io.
 _Avoid_: "private registry" (collides with the registry VM's pull-through caches); pushing new images to it.

docs/adr/0003-keep-forgejo-canonical-complete-mirror.md

@@ -0,0 +1,30 @@
+# Keep Forgejo as the canonical forge; complete the one-way GitHub mirror instead of swapping to GitHub
+
+Status: accepted (extends ADR-0002)
+
+## Context
+
+Repo trees kept diverging between the Forgejo **Canonical repo** (`viktor/<name>`) and its **GitHub mirror**. A 2026-06-15 audit found the cause: an *incomplete rollout* of the Forgejo→GitHub push-mirror, not anything inherent to Forgejo. 14 repos carry **both** remotes and are hand-pushed to each (`push_mirrors = 0` on Forgejo — e.g. `infra`, `finance`, `Website`), so a human forgets one side and the trees drift; the ADR-0002-onboarded repos have a working one-way mirror (`push_mirrors = 1` — e.g. `tripit`, `recruiter-responder`) and never diverge. `infra/CONTEXT.md` already says Forgejo is the only place commits land and the GitHub mirror must never be a second writable remote — practice had simply drifted from the documented model.
+
+The trigger was a proposal to swap Forgejo out for GitHub entirely. The grilling reframed it: the pain (divergence) is a "two writable remotes" problem, and the stated preference is self-hosted-primary with the remote as backup.
+
+## Decision
+
+Do **not** swap to GitHub. Reaffirm and *complete* the model already in `CONTEXT.md`:
+
+- Every first-party repo has exactly **one** push target — its **Canonical repo** on Forgejo. GitHub is a one-way push-mirror (off-site backup + the source GitHub Actions builds from). **No repo is ever dual-pushed.**
+- A small, explicit set of **GitHub-first repos** are the exception (canonical lives on GitHub, outside the mirror policy): third-party clones/forks where GitHub is genuinely upstream (`jsoncrack.com`, `snmp_exporter`, `SparkyFitness`, `agent-rules-books`, `Plotting-Your-Dream-Book`) and the deliberately-public first-party `health`.
+- `infra` is reconciled into the standard model: its GitHub-only `.github/workflows/build-*.yml` are brought onto Forgejo-canonical (inert on Forgejo, active on the mirror), then the mirror is enabled — ending the deliberate divergence while keeping Woodpecker on the Forgejo forge.
+- Enforcement is **structural**: reconciled clones keep only the Forgejo remote, so there is no GitHub remote to habitually push to; the execution rule is "push to the canonical forge only, never the mirror."
+
+## Considered options
+
+- **Swap to GitHub (retire Forgejo).** Rejected: takes on a hard WAN dependency for *all* git ops — including `infra`, the repo you use to *recover* from outages — plus git-crypt secrets on GitHub as primary, a Woodpecker forge migration (WP authenticates against and watches Forgejo), and GitHub private-repo CI-minute/size limits. All to fix a problem that is actually an incomplete mirror, not Forgejo's existence. Contradicts the self-hosted-primary preference.
+- **GitHub canonical, Forgejo demoted to a DR pull-mirror.** Rejected for the same WAN-dependency and forge-migration cost; unnecessary once the real cause is understood.
+
+## Consequences
+
+- Divergence becomes structurally impossible — one push target per repo.
+- Forgejo stays load-bearing (canonical git + the Woodpecker forge), so every cost of the swap is avoided.
+- The GitHub-limits worry is neutralized: private code lives on Forgejo (unlimited, self-hosted); GitHub holds mirrors for CI + backup. (GitHub Free has unlimited private repos anyway; the real limits are GHA minutes and ~1 GB repo size — `travel_blog` at 1.4 GB is why it never went to GHA.)
+- One-time remediation is required and carries a data-loss footgun: the Forgejo→GitHub mirror **force-overwrites** GitHub, so for each currently-diverged repo, any GitHub-only commits must be merged into Forgejo **before** the mirror is enabled, or they are lost. Scope: the 14 dual-push repos + the `infra` reconciliation; all other repos are already single-remote and non-diverging.