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, 1 insertions, 0 deletions

diff --git a/tsconfig.json b/tsconfig.json
index fdf58f5..505d883 100644
--- a/tsconfig.json
+++ b/tsconfig.json
@@ -8,6 +8,7 @@
 		{ "path": "./packages/conversation-store" },
 		{ "path": "./packages/session-orchestrator" },
 		{ "path": "./packages/transport-http" },
+		{ "path": "./packages/tool-read-file" },
 		{ "path": "./packages/host-bin" }
 	]
 }