chore: remove dead code (59 unused files + ~125 unused exports) (#1835)

* chore: remove dead/unreferenced files across ui, vscode

Remove 59 unused source files (components, hooks, lib utils, stores,
barrels, and orphaned vscode github modules) that are not imported by
any entry-reachable code. Also drop a stale test mock for the removed
execCommands module.

Co-authored-by: Serhii Dziupin <makeittech@users.noreply.github.com>

* refactor: remove unused exported symbols (types, functions, consts, hooks)

Remove exported symbols whose identifier is referenced nowhere in the
repository (verified via repo-wide search), across ui types/contracts,
lib utilities, sync layer, stores, and components. Also drop the few
imports/private helpers orphaned by these removals.

Co-authored-by: Serhii Dziupin <makeittech@users.noreply.github.com>

* refactor: remove more unused exports (desktop, shortcuts, worktree, vscode)

Continue removing repo-wide unreferenced exported functions, consts and
types across lib/desktop, shortcuts, worktreeSessionCreator, sync, and
vscode gitService, with cascading orphaned helpers/imports cleaned up.

Co-authored-by: Serhii Dziupin <makeittech@users.noreply.github.com>

* chore: add dead-code cleanup tooling

* refactor: checkpoint dead-code cleanup

* refactor: remove dead-code suppressions

---------

Co-authored-by: Serhii Dziupin <makeittech@users.noreply.github.com>
Co-authored-by: Bohdan Triapitsyn <artmore@protonmail.com>

packages/web/server/lib/skills-catalog/source.js

@@ -1,4 +1,5 @@
 const GITHUB_HOST = 'github.com';
+const CLAWDHUB_SOURCE_PREFIX = 'clawdhub:';
 
 
 function normalizeGitOwnerRepo(owner, repo) {
@@ -85,3 +86,7 @@ export function parseSkillRepoSource(input, options = {}) {
 
   return { ok: false, error: { kind: 'invalidSource', message: 'Unsupported repository source format' } };
 }
+
+export function isClawdHubSource(input) {
+  return typeof input === 'string' && input.trim().toLowerCase().startsWith(CLAWDHUB_SOURCE_PREFIX);
+}