feat: add the kettle CLI, replacing the plugin's Python scripts

The plugin resolved its issue store from `__file__`, which put it inside a
versioned plugin cache: issues written from one project were invisible from the
next, and `origin: local` files — the only copy of that work by definition —
were stranded a version bump at a time. The walk that answers "which directory
is the project" was written three times over, and in a linked worktree the three
disagreed. Both are runtime failures rather than logic ones, so the fix is a
compiled binary: one walk, imported rather than re-derived, and a layering rule
the build graph enforces instead of a grep.

Seven packages, knowledge flowing one way. `project` answers which directory is
the project and depends on nothing. `issue` is the domain — format, taxonomy,
validation, checkboxes, dependency graph, the store, eviction — offline, with no
tracker in it. `wire` holds the protocol shapes. `gitea` is the transport,
`mapping` the bridge, `config` the credentials, `cmd` the command tree. Four
tests hold the boundaries, each failing on a real mistake rather than a naming
convention.

The marker moves to `.kettle/` and the login pin moves out of the harness's
settings file into `.kettle/config.yaml`, which pins a login by NAME; the tokens
live in one file per machine, mode 0600, outside every working tree. That
retires the PreToolUse guard hook entirely — the binary holds its own
credentials, so a command running under a login nobody chose is not expressible
rather than caught.

`kettle init` migrates an older `tmp/issues` or `.tea/issues` store in, as a
move: a store left behind at an old path is one somebody edits by accident
months later.

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

cli/internal/cmd/sync.go

@@ -0,0 +1,70 @@
+package cmd
+
+import (
+	"path/filepath"
+
+	"git.noodles.cam/claude-skills/marketplace/cli/internal/config"
+	"git.noodles.cam/claude-skills/marketplace/cli/internal/gitea"
+	"git.noodles.cam/claude-skills/marketplace/cli/internal/issue"
+)
+
+// commentsSidecarPath is where an issue's comment thread lives — beside it,
+// under the same slug.
+//
+// A path, not a concept the domain needs: a thread is pulled from the tracker
+// and never pushed back, so `internal/issue` has no reason to learn that the
+// file exists. It does not have to — the file is named after the issue, and
+// issue.SlugFiles takes it away when the issue goes.
+//
+// It sits here rather than in either command because `pull` writes it and
+// `comment` rewrites it, and two spellings of one path is how the two come to
+// disagree about where a thread is.
+func commentsSidecarPath(root, id string) string {
+	return filepath.Join(root, id+".comments.md")
+}
+
+// The sync commands all start the same way and must fail the same way.
+//
+// Every one of them needs a store and a client, and the order matters: a
+// command that dialled first would report a network problem for a project that
+// was never initialized, and an operator would go looking at the wrong thing.
+// So the store is resolved before a socket is opened, and each failure names
+// the command that fixes it.
+
+// syncStart resolves the store and builds a client for it.
+//
+// The client is built from the project's own configuration, which is why there
+// is no --login flag anywhere in this tree: which login a project runs under is
+// a fact about the project, stated once by `kettle init`, not a thing a caller
+// gets to differ about per invocation. That the two could disagree is what the
+// Python version needed a PreToolUse hook to police.
+func syncStart(out string) (string, *gitea.Client, error) {
+	root, err := storeRoot(out)
+	if err != nil {
+		return "", nil, err
+	}
+	cfg, err := config.Require("")
+	if err != nil {
+		return "", nil, err
+	}
+	client, err := gitea.New(cfg)
+	if err != nil {
+		return "", nil, err
+	}
+	return root, client, nil
+}
+
+// syncStartExisting is syncStart for the commands that read the store rather
+// than create it: push, comment, close and the sync form of evict all operate
+// on issues that are already on disk, and a missing store is a mistake to
+// report, not a directory to conjure.
+func syncStartExisting(out string) (string, *gitea.Client, error) {
+	root, client, err := syncStart(out)
+	if err != nil {
+		return "", nil, err
+	}
+	if err := issue.RequireStore(root); err != nil {
+		return "", nil, err
+	}
+	return root, client, nil
+}