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

instructions/kb-profiles.md

@@ -15,8 +15,8 @@ it lives.
 
 That direction is deliberate and it is the opposite of how this repo used to work. Language,
 tone, naming and the relationship vocabulary sat in `kb/CONTRACT.md`, a file `dist export` ships
-verbatim - so every instance that wanted something else edited a stack file, and an upstream
-merge handed the stack's answer back. What binds is now the instance's; what ships is this
+verbatim - so every instance that wanted something else edited a stack file, and the next update
+handed the stack's answer back. What binds is now the instance's; what ships is this
 catalogue, and it binds nothing.
 
 <!-- wikitool:toc -->
@@ -221,8 +221,8 @@ optional.
   [migrate-corpus.md](migrate-corpus.md).
 - **Tempted to make this page binding** - to have `COLLECTION.md` say `profile: entities` and
   nothing else? Do not. That is the arrangement this split was written to end: the instance
-  would be bound by a file the stack ships and upgrades, which is how an upstream merge changes
-  an instance's authoring rules without anyone deciding to.
+  would be bound by a file the stack ships and upgrades, which is how an update changes an
+  instance's authoring rules without anyone deciding to.
 
 ## Scope