feat!: installation only from a release, into an empty folder; upstream merge/verify and private-instance.md removed, dist adopt, shell-neutral instructions (#153)

Files changed:
- .gitea/workflows/ci.yml
- .gitea/workflows/release.yml
- AGENTS.md
- CHANGES.md
- DEVELOPMENT.md
- EVALS.md
- INSTALL.md
- README.md
- VERSION
- docs/ownership-and-templates.md
- instructions/CONTRACT.md
- instructions/bootstrap.md
- instructions/dev/dev-setup.md
- instructions/dev/stack-dev/SKILL.md
- instructions/gates.md
- instructions/ingest-large-tree.md
- instructions/kb-profiles.md
- instructions/mcp-read-server.md
- instructions/migrations/3.0.0-authoring-conventions.md
- instructions/preflight.md
- instructions/private-instance.md
- instructions/session-setup.md
- instructions/setup-instance.md
- instructions/upgrade-instance.md
- tools/CONTRACT.md
- tools/README.md
- tools/chemenu/cli.py
- tools/chemenu/cli_contract.py
- tools/chemenu/commands/dist_cmd.py
- tools/chemenu/commands/docs_verify.py
- tools/chemenu/commands/doctor.py
- tools/chemenu/commands/git_publish.py
- tools/chemenu/commands/upstream_cmd.py
- tools/chemenu/commands/work_cmd.py
- tools/chemenu/config.py
- tools/chemenu/ownership.py
- tools/chemenu/tests/test_cli.py
- tools/chemenu/tests/test_dist_cmd.py
- tools/chemenu/tests/test_instructions_shell.py
- tools/chemenu/tests/test_preflight.py
- tools/chemenu/tests/test_preflight_pwsh.py
- tools/chemenu/tests/test_run_budget.py
- tools/chemenu/tests/test_upstream_cmd.py
- tools/chemenu/toc.py
- tools/preflight.ps1
- tools/preflight.sh

AGENTS.md

@@ -37,12 +37,10 @@ missing or empty - a fresh clone - the harness offers no skills until they are p
 tools/wikitool instructions sync
 ```
 
-Full procedure, including the tool environment: [instructions/bootstrap.md](instructions/bootstrap.md).
-Setting up a brand-new, empty instance instead of cloning this one: `tools/wikitool dist export`
-and [instructions/setup-instance.md](instructions/setup-instance.md) - see
-[INSTALL.md](INSTALL.md). A *private* instance that keeps taking stack updates from a public
-upstream is a third shape, with a safeguard the other two do not need:
-[instructions/private-instance.md](instructions/private-instance.md).
+Full procedure for a fresh clone of an instance, including the tool environment:
+[instructions/bootstrap.md](instructions/bootstrap.md). Setting up a brand-new, empty instance
+instead: [instructions/setup-instance.md](instructions/setup-instance.md), which installs the
+latest release into an empty folder - see [INSTALL.md](INSTALL.md).
 
 ## Invariants
 
@@ -149,7 +147,8 @@ command touches it.
 Six pages are reached from this file, each by link rather than automatically:
 [docs/pipeline-rationale.md](docs/pipeline-rationale.md) (why the pipeline has four stages),
 [docs/ownership-and-templates.md](docs/ownership-and-templates.md) (why a `.template` split
-exists, and why silent overwrite is the failure it guards against),
+exists, why silent overwrite is the failure it guards against, and why an instance comes only
+from a release),
 [docs/language-boundaries.md](docs/language-boundaries.md) (why the control plane is English
 everywhere and the KB language is a value, and why the axis is the reader rather than the
 owner), [docs/why-gates-are-code.md](docs/why-gates-are-code.md) (why the four gates in
@@ -337,7 +336,10 @@ see [Gates](#gates).
 Extending `tools/wikitool`, the type schema, or the instruction/skill layer itself (rather than
 operating on wiki content) is a different session type with different rules - see the
 `stack-dev` skill, nested under [instructions/dev/](instructions/dev/) along with the
-procedures it routes to. Never present in a distributed instance.
+procedures it routes to. Setting up a clone of this origin repository for that work - the demo
+corpus, the preflight, `dist export` as a build and test tool - is
+[instructions/dev/dev-setup.md](instructions/dev/dev-setup.md). Never present in a distributed
+instance.
 <!-- dist:strip-end -->
 
 ## Changelog