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, 8 insertions, 0 deletions

diff --git a/packages/core/tests/config/loader.test.ts b/packages/core/tests/config/loader.test.ts
index de025de..0d84d0b 100644
--- a/packages/core/tests/config/loader.test.ts
+++ b/packages/core/tests/config/loader.test.ts
@@ -6,12 +6,20 @@ import { configToRuleset, loadConfig } from "../../src/config/loader.js";
 
 const TMP = join("/tmp/opencode", "dispatch-config-test");
 
+// Point the global config at a path that does not exist so these tests are
+// hermetic — they must not pick up this machine's real
+// ~/.config/dispatch/dispatch.toml.
+const prevGlobal = process.env.DISPATCH_GLOBAL_CONFIG;
+
 beforeEach(() => {
 	mkdirSync(TMP, { recursive: true });
+	process.env.DISPATCH_GLOBAL_CONFIG = join(TMP, "__no_such_global__.toml");
 });
 
 afterEach(() => {
 	rmSync(TMP, { recursive: true, force: true });
+	if (prevGlobal === undefined) delete process.env.DISPATCH_GLOBAL_CONFIG;
+	else process.env.DISPATCH_GLOBAL_CONFIG = prevGlobal;
 });
 
 function writeToml(content: string): void {