feat(tool-read-file): add read_file tool extension + wire into host-bin

First TOOL extension (standard tier, fs capability). Pure-core/shell split with
workdir containment (realpath symlink guard). host-bin registers it in
CORE_EXTENSIONS; flows into runTurn via session-orchestrator's resolveTools.

Verified: typecheck clean, 214 tests pass (was 185), biome clean. Live curl
against flash produced a real tool-call + tool-result round-trip with correct
final answer. Proves the kernel tool-dispatch loop end-to-end (plan §3.3).

1 files changed, 10 insertions, 0 deletions

diff --git a/bun.lock b/bun.lock
index 6fa16ea..0c5b609 100644
--- a/bun.lock
+++ b/bun.lock
@@ -35,6 +35,7 @@
         "@dispatch/provider-openai-compat": "workspace:*",
         "@dispatch/session-orchestrator": "workspace:*",
         "@dispatch/storage-sqlite": "workspace:*",
+        "@dispatch/tool-read-file": "workspace:*",
         "@dispatch/transport-http": "workspace:*",
       },
     },
@@ -64,6 +65,13 @@
         "@dispatch/kernel": "workspace:*",
       },
     },
+    "packages/tool-read-file": {
+      "name": "@dispatch/tool-read-file",
+      "version": "0.0.0",
+      "dependencies": {
+        "@dispatch/kernel": "workspace:*",
+      },
+    },
     "packages/transport-http": {
       "name": "@dispatch/transport-http",
       "version": "0.0.0",
@@ -107,6 +115,8 @@
 
     "@dispatch/storage-sqlite": ["@dispatch/storage-sqlite@workspace:packages/storage-sqlite"],
 
+    "@dispatch/tool-read-file": ["@dispatch/tool-read-file@workspace:packages/tool-read-file"],
+
     "@dispatch/transport-http": ["@dispatch/transport-http@workspace:packages/transport-http"],
 
     "@esbuild/aix-ppc64": ["@esbuild/[email protected]", "", { "os": "aix", "cpu": "ppc64" }, "sha512-EKX3Qwmhz1eMdEJokhALr0YiD0lhQNwDqkPYyPhiSwKrh7/4KRjQc04sZ8db+5DVVnZ1LmbNDI1uAMPEUBnQPg=="],