feat(config): merge home-directory global dispatch.toml under project config

Load an optional global config at ~/.config/dispatch/dispatch.toml
(override via DISPATCH_GLOBAL_CONFIG) and deep-merge it underneath every
project/working-directory dispatch.toml, so machine-wide settings — most
notably globally available LSP servers — work in any repo without per-repo
config. Local always wins on conflicts.

- loader: add getGlobalConfigPath(), loadGlobalConfig(), mergeConfigs();
  loadConfig(dir) now loads+merges global. [lsp] and [[keys]] merge by id;
  [permissions] merge per-group with global patterns emitted first so local
  rules win at evaluation time (findLast). A malformed global config is
  downgraded to empty rather than breaking every repo.
- watcher: watch BOTH global and local dispatch.toml so hot-reload re-merges
  on either change (dedupes when paths coincide).
- export new loader fns from config/index and core index.
- types/agent-manager: doc updates reflecting merged LSP resolution.
- dispatch.toml: document global-default merge behavior; activate biome and
  typescript-language-server LSP entries.
- tests: merge precedence, lsp/keys merge-by-id, permissions merge,
  filesystem integration, malformed-global resilience; isolate global path
  in existing loader tests.

1 files changed, 7 insertions, 1 deletions

diff --git a/packages/core/src/config/index.ts b/packages/core/src/config/index.ts
index 5b128c4..4806409 100644
--- a/packages/core/src/config/index.ts
+++ b/packages/core/src/config/index.ts
@@ -1,3 +1,9 @@
-export { configToRuleset, loadConfig } from "./loader.js";
+export {
+	configToRuleset,
+	getGlobalConfigPath,
+	loadConfig,
+	loadGlobalConfig,
+	mergeConfigs,
+} from "./loader.js";
 export { validateConfig } from "./schema.js";
 export { createConfigWatcher } from "./watcher.js";