docs: READMEs describe current behaviour, not history

Removes the decision logs, the dated rows, the strikethrough retirements and
the setup progress checkboxes from all four READMEs. A decision log records how
the system came to be; a reader needs to know how it is. The two had drifted
far enough apart that the docs asserted things the shipped config contradicted.

Corrected, all of which were stale rather than merely verbose:

- the architecture section described the source-repo workflow as self-contained
  and called the reusable workflows here "not actively called; may be stale".
  They are the pipelines; the source-repo workflow is a thin caller.
- `workflow_call` was recorded as abandoned, and the instance as having no orgs.
  Both pipelines run through cross-repo `workflow_call` under an org.
- tech-blogs was described as not yet initialised. It has published.
- ses and tech invocation sections claimed a self-contained workflow too.

Kept, rewritten as behaviour rather than as dated decisions, because they are
live operational constraints and not history:

- the callee workflow cache, why a `publish-*.yml` edit appears not to take,
  and the flush command with its `--no-deps` and `--pull` caveats
- why this repo has to stay public
- the `URL_TO_GITEA` / `PUBLIC_URL_TO_GITEA` split and what validates it
- host network mode, and that `kaniko-act` cannot be rebuilt by build-image.yml

Also documents what the renderer, its failure modes and its publish scope
actually are, which the decision logs had been standing in for, and adds the
architecture note that renderer code is cloned fresh per run while workflow
YAML is cached — the distinction that governs whether a change takes effect.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

pipelines/tech/README.md

@@ -5,7 +5,7 @@ Publishes tech blog posts from `novoyuuparosk-wiki/tech-blogs` to `https://wiki.
 - Source-file contract (frontmatter and body conventions): [SCHEMA.md](SCHEMA.md)
 - Cross-cutting setup (wiki URL, bot identity, runner, Gitea secrets/variables): [repo root README](../../README.md)
 
-## v1 scope
+## What the renderer does
 
 - YAML frontmatter parsing per [SCHEMA.md](SCHEMA.md)
 - Pandoc-based markdown → wikitext body rendering (h1 elements preserved)
@@ -18,9 +18,9 @@ Publishes tech blog posts from `novoyuuparosk-wiki/tech-blogs` to `https://wiki.
 
 ## Source repo
 
-Source repo: `novoyuuparosk-wiki/tech-blogs` (not yet initialised — pipeline code is ready).
+Source repo: `novoyuuparosk-wiki/tech-blogs`, triggering on push to `master`, with `workflow_dispatch` for manual runs.
 
-The pipeline triggers on push to `master` and supports `workflow_dispatch` for manual runs.
+No branch convention enforced. There is no `wip/` exclusion — `wiki.publish: true` is the only publishing gate.
 
 **Excluded paths** (won't trigger the pipeline):
 
@@ -28,12 +28,18 @@ The pipeline triggers on push to `master` and supports `workflow_dispatch` for m
 
 ## Invocation
 
-The pipeline runs as a self-contained Gitea Actions workflow in `novoyuuparosk-wiki/tech-blogs` (`.gitea/workflows/publish.yml`). It clones this repo at runtime to get the renderer.
+`novoyuuparosk-wiki/tech-blogs/.gitea/workflows/publish.yml` is a thin caller: it triggers, then `uses:` [`publish-tech.yml`](../../.gitea/workflows/publish-tech.yml) here, which clones both repos and runs `publish.py`.
+
+Editing `publish-tech.yml` requires a runner cache flush before it takes effect; the renderer itself is cloned fresh every run. See *Callee workflow cache* in the [root README](../../README.md).
 
 Triggers:
 - `push` to `master` (path-filtered as above)
 - `workflow_dispatch` — manual trigger from the Gitea Actions UI
 
+### Publish scope
+
+Every run publishes every file with `wiki.publish: true`; there is no diff detection. Writes are idempotent — the banner carries the commit SHA rather than a timestamp, so a re-run at the same commit rewrites nothing.
+
 ### Environment (secrets and variables)
 
 | Name | Kind | Source | Purpose |
@@ -50,30 +56,8 @@ Triggers:
 
 ## Dependencies
 
-Job container: `novoyuuparosk-wiki-runner:latest` (pre-built, stored in the local Docker daemon on the runner host). Bakes in Python 3.12, Pandoc, and all pipeline Python packages — no install steps at job runtime.
+Job container image and its build are described in the [root README](../../README.md#job-container-image). Python packages for this pipeline are in `requirements.txt` here; changing it triggers an image rebuild. Shared render and MediaWiki helpers live in `lib/wiki.py` at the repo root.
 
-See the `Dockerfile` at the repo root and `requirements.txt` in this directory. Rebuild the image after changes to either.
+## Wiki-side prerequisites
 
-Shared code lives in `lib/wiki.py` (repo root).
-
-## One-off wiki setup
-
-- [ ] **`Template:Auto-generated`** — must exist on the wiki (shared with all pipelines; already created).
-
-## Decisions log (tech pipeline)
-
-| Decision | Value | Date |
-|---|---|---|
-| No title prefix | Tech posts live at bare titles — no namespace needed | 2026-06-10 |
-| Fixed category | Every post gets `Category:Tech blog` | 2026-06-10 |
-| Year category | `Category:Blog:<year>` from `date` field; falls back to the execution year if no date | 2026-06-10 |
-| Tag categories | Each tag → `[[Category:<tag>]]` with no prefix | 2026-06-10 |
-| WIP exclusion | None — `wiki.publish: false` is the only gate | 2026-06-10 |
-| Publish mode | Always `--all` | 2026-06-10 |
-| Idempotency | Commit SHA in banner | 2026-06-10 |
-| Manual-page protection | Bot skips pages without `{{Auto-generated` banner | 2026-06-10 |
-| Source repo | `novoyuuparosk-wiki/tech-blogs` — pipeline ships before repo is initialised | 2026-06-10 |
-
-## Status
-
-v1 pipeline ready. Source repo (`novoyuuparosk-wiki/tech-blogs`) not yet initialised.
+**`Template:Auto-generated`** must exist on the wiki. It is shared across all three pipelines; the wikitext source lives in [`pipelines/songs/template_auto_generated.wikitext`](../songs/template_auto_generated.wikitext).