feat(cli): smart defaults and flatter command surface for ktx (#177)

Bare invocations now do the obvious thing instead of erroring out, and mode-as-subcommand patterns collapse into flags on the parent. No new top-level commands.

- `ktx ingest` (bare) ingests every configured connection. The `text` subcommand is gone; capture inline notes with `ktx ingest --text "..."` and files with `ktx ingest --file path` (use `-` for stdin). `--text`/`--file` reject a positional connection id; pass `--connection-id` to tag captured notes.
- `ktx connection` (bare) lists; `ktx connection test` (bare) tests every configured connection.
- `ktx wiki` and `ktx sl` flatten `list`/`search`: bare lists, with a `[query...]` positional searches (multi-word joined with spaces). `sl validate` and `sl query` stay as distinct verbs and now read `--connection-id` from the parent.
- `ktx mcp` (bare) prints daemon status.

Adds a shared `resolveConnectionSelection` helper consumed by ingest and connection test. Updates README, docs-site cli-reference and guides, next-steps strings, agent SKILL templates, and all affected tests. Per-package type-check, unit tests (605), smoke tests, and dead-code checks all pass.

packages/cli/src/io/print-list.test.ts

@@ -78,14 +78,14 @@ describe('printList — plain mode', () => {
       mode: 'plain',
       command: 'sl search',
       emptyMessage: 'No sources matched "foo"',
-      emptyHint: 'Run `ktx sl list` to see available sources.',
+      emptyHint: 'Run `ktx sl` to see available sources.',
       unit: 'source',
       io: r.io,
     });
     expect(r.out()).toBe('');
     expect(r.err()).toBe(
       'No sources matched "foo"\n' +
-      'Run `ktx sl list` to see available sources.\n',
+      'Run `ktx sl` to see available sources.\n',
     );
   });
 });
@@ -188,13 +188,13 @@ describe('printList — pretty mode', () => {
       mode: 'pretty',
       command: 'sl search',
       emptyMessage: 'No sources matched "foo"',
-      emptyHint: 'Run `ktx sl list` to see available sources.',
+      emptyHint: 'Run `ktx sl` to see available sources.',
       unit: 'source',
       io: r.io,
     });
     const out = stripAnsi(r.out());
     expect(out).toContain('No sources matched "foo"');
-    expect(out).toContain('Run `ktx sl list` to see available sources.');
+    expect(out).toContain('Run `ktx sl` to see available sources.');
   });
 
   it('singularizes the footer when there is one row', () => {