refactor!: rewire the plugin onto the kettle binary, and rename it

BREAKING: the plugin is `kettle`, not `tea`, and its commands are `/kettle:*`.
It also now needs a binary on PATH that it did not need before; the README and
every skill say how to get one and what a missing one looks like.

The plugin was 3800 lines of Python doing what a compiled binary does better,
and the name pointed at a tool that no longer takes part: `tea` is Gitea's CLI,
and since the transport moved into the binary nothing here shells out to it for
issues at all. A plugin named after it was going to keep suggesting otherwise.

Deleted: 19 scripts, the 14-file unittest suite, and the tea-guard hook. The
guard blocked any `tea` invocation that would run under a login the model picked
instead of the operator; the binary holds its own credentials and reads the
pinned login out of the project's own config, so that failure is no longer
expressible and there is nothing left to police. agents-sync stays — it is about
AGENTS.md symlinks and has nothing to do with any of this.

What the plugin keeps is what only a plugin can carry: the rules an operator
states and a binary cannot enforce. `init` still refuses to run inside a linked
worktree and still may not be model-invoked, because which directory is the
project is a statement a person makes. The issue format reference stays here and
stays the source of truth. The runner subagent is still for batches and still
may not decide what an issue says.

The command reference in the issue, sync and project skills is GENERATED from
the binary's own command registry, between markers, so a flag that changed
cannot ship with a skill that recommends the old one. `kettle gen skills
--check` exits non-zero when they drift. The generator owns the region and
nothing outside it: the frontmatter description, which is what decides whether a
skill loads at all, stays hand-written.

`use` survives and is the one place `tea` is still named — for releases,
webhooks and actions, which kettle does not cover. Its instruction to write
`--login "$GITEA_LOGIN"` and let the hook substitute the pin was true until this
commit and is now rewritten: `tea` keeps its own configuration, kettle keeps
its own, and configuring one configures nothing in the other.

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

cli/internal/cmd/gen.go

@@ -62,9 +62,9 @@ property made useful: it writes nothing and exits 1 when any file on disk
 differs from what would be generated, which is what a pre-commit hook or a CI
 step calls. It wins over --dry-run when both are given.`,
 		Examples: []Example{
-			{"kettle gen skills --out ../plugins/tea/skills", "write the region in every group's SKILL.md"},
-			{"kettle gen skills --out ../plugins/tea/skills --dry-run", "print what would change; write nothing"},
-			{"kettle gen skills --out ../plugins/tea/skills --check", "exit 1 if the docs are out of date"},
+			{"kettle gen skills --out ../plugins/kettle/skills", "write the region in every group's SKILL.md"},
+			{"kettle gen skills --out ../plugins/kettle/skills --dry-run", "print what would change; write nothing"},
+			{"kettle gen skills --out ../plugins/kettle/skills --check", "exit 1 if the docs are out of date"},
 		},
 		Setup: func(fs *flag.FlagSet) func([]string) error {
 			out := fs.String("out", "", "directory the skills live in; one <group>/SKILL.md under it")

cli/internal/cmd/init.go

@@ -76,11 +76,11 @@ one would write issues into whatever it happened to be installed in.
 machine, outside every working tree, managed with ` + "`kettle auth`" + `.
 
 All of it is idempotent: it creates .kettle/issues and .kettle/payload, migrates
-an older store in if it finds one (tmp/ or .tea/), writes the config without
-disturbing settings it was not given, and adds .kettle/ to .gitignore. Each
-migration is a move, not a copy — two stores is the state the marker exists to
-prevent — and it refuses to pick a winner when both sides hold a file of the
-same name.
+an older store in if it finds one (either layout the tea plugin used, oldest
+first), writes the config without disturbing settings it was not given, and adds
+.kettle/ to .gitignore. Each migration is a move, not a copy — two stores is the
+state the marker exists to prevent — and it refuses to pick a winner when both
+sides hold a file of the same name.
 
 Do NOT run this inside a linked worktree. A worktree is the same project on
 another branch and reaches the store by a hop out to the main checkout; a marker

cli/internal/cmd/new.go

@@ -23,7 +23,7 @@ While it says local, this file is the ONLY copy of the work — the store, not a
 cache of anything. That is what a push changes: it hands the issue to the
 tracker and removes the file.
 
-Writes .tea/issues/<slug>.md prefilled with the type's template, prints the
+Writes .kettle/issues/<slug>.md prefilled with the type's template, prints the
 path, and rebuilds INDEX.md. Fill the sections in an editor, then run
 ` + "`kettle check <id>`" + `.
 
@@ -31,7 +31,7 @@ Body prose is Russian, section headers and the title are English.`,
 		Examples: []Example{
 			{`kettle new --type task --title "Wire sqlc into the appclick repo layer" --label tech/sql --label comp/appclick`,
 				"a task with two free-form labels"},
-			{`kettle new --type bug --title "Fix tea-guard crash on empty settings" --depends wire-sqlc-appclick --milestone v0.2`,
+			{`kettle new --type bug --title "Fix the index rebuild on an empty store" --depends wire-sqlc-appclick --milestone v0.2`,
 				"a bug that is blocked by another issue"},
 		},
 		Setup: func(fs *flag.FlagSet) func([]string) error {

cli/internal/cmd/tree.go

@@ -24,7 +24,7 @@ this works identically for issues that were never pushed anywhere.
 Downwards is what this draws — what an issue depends on. The other direction is
 a grep, not a flag:
 
-    grep -ln 'depends:.*migrate-schema' .tea/issues/*.md`,
+    grep -ln 'depends:.*migrate-schema' .kettle/issues/*.md`,
 		Examples: []Example{
 			{"kettle tree", "every root (nothing depends on it)"},
 			{"kettle tree wire-sqlc-appclick", "one subtree"},