docs: record M4 results and simulator findings; bump to 0.4.0v0.4.0

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

1 files changed, 7 insertions, 0 deletions

diff --git a/docs/FEASIBILITY.md b/docs/FEASIBILITY.md
index c16b0ce..f586f10 100644
--- a/docs/FEASIBILITY.md
+++ b/docs/FEASIBILITY.md
@@ -267,6 +267,13 @@ With SDK 9.2.0 and the device files of all 72 products installed:
 - **Invalid UTF-8 crashes the string conversion.** `StringUtil.convertEncodedString` stops the app with an uncatchable system error instead of throwing; stored text is validated before decoding.
 - **Store-full handling is tested only against a simulated store.** The in-memory test store throws `StorageFullException` at a set size. How the real store behaves when full is checked on the watch (real-watch checklist in [TESTING.md](TESTING.md)).
 
+## Verified during M4 (2026-10-19)
+
+- **Watchdog (2): enforced in normal simulator runs, not in unit tests.** The limit is the device's `watchdogCount` per event. On the Forerunner 255S (120,000) it stopped 200 PBKDF2 iterations in one event and two SHA-512 codes in one draw. One SHA-512 TOTP code per event fits. Long work is split accordingly ([PERFORMANCE.md](PERFORMANCE.md)).
+- **Glances (7):** the simulator starts a watch app that has a glance in the glance, and the app opens with a tap (touch) or DOWN then START (buttons). The glance and the full app run separately: the app object's `initialize` runs before the non-glance code is loaded.
+- **Properties:** reading a property that isn't declared in `properties.xml` stops the app with an error `try` can't catch. The option properties are declared ahead of M7's form.
+- **Touch input:** on watches with touch and buttons, a tap arrives first as the select behaviour. The Venu X1 has no MENU button, and the Venu Sq 2 has no UP/DOWN.
+
 ## Decisions
 
 Answered on 2026-10-18: