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, 5 deletions

diff --git a/packages/api/src/agent-manager.ts b/packages/api/src/agent-manager.ts
index 7cfa03c..913fb15 100644
--- a/packages/api/src/agent-manager.ts
+++ b/packages/api/src/agent-manager.ts
@@ -390,11 +390,14 @@ export class AgentManager {
 	/**
 	 * Resolve (and cache) the LSP servers configured for a working directory.
 	 *
-	 * LSP config is project-scoped: it lives in the `dispatch.toml` of the
-	 * tab's effective working directory, NOT the global config. We read that
-	 * directory's config once and cache the resolved servers; the cache is
-	 * cleared on config hot-reload. Returns `[]` when the directory has no
-	 * `[lsp]` block (the common case).
+	 * LSP config is resolved by `loadConfig`, which merges the HOME-directory
+	 * global `dispatch.toml` (`~/.config/dispatch/dispatch.toml`) underneath the
+	 * tab's effective working-directory `dispatch.toml` — local `[lsp.<id>]`
+	 * entries override global ones sharing the same id, while global-only
+	 * servers stay active in every repository. We read+merge that config once
+	 * per directory and cache the resolved servers; the cache is cleared on
+	 * config hot-reload. Returns `[]` when neither config declares an `[lsp]`
+	 * block (the common case).
 	 */
 	private getLspServersForDir(dir: string): ResolvedLspServer[] {
 		const cached = this.lspServersByDir.get(dir);