docs(release): 0.5.0 notes carry the session-timer init-once fix

The fix landed on PR #28 (96806fe) after the third CI timeout of the
two-tab 409 e2e test named its mechanism from the captured state. The
CHANGELOG says what the learner saw and what changed; the release note
keeps it to the one-line consequence beside the other correctness fixes.

Author: NetDevAutomate

CHANGELOG.md

@@ -151,6 +151,14 @@ experience may change before `1.0.0`.
   literal marker `>-`, so it printed no reason and would have accepted an
   empty one — the unexplained deferral the guard exists to refuse. It now
   reads the indented text and refuses an empty block.
+- The Study Session view's timer ran its `init()` twice per page load (Alpine's
+  own call plus the markup's `x-init`), each run reading `/api/session/state`.
+  A tab sitting on the session picker could adopt a session started in
+  another tab when the slower read landed — Start hidden under the live
+  layout, no 409, no reattach offer. `init()` now runs once per page load;
+  a second tab's Start reaches the server and is offered reattach. Named by
+  the state captured at the click in CI (third occurrence, first with
+  evidence) and pinned by a `node --test` replay of that race.
 
 ### Security
 

releases/v0.5.0.md

@@ -91,6 +91,11 @@ does not advertise GitHub or PyPI binary distribution.
   was just spared as the primary with its own deferral printed beneath it.
   Found by emitting the owner's rubric readings through both readers; the
   earlier fixture had silenced one.
+- The Study Session timer's `init()` ran twice per page load, each run
+  reading the live-session state; the slower read could adopt a session
+  started in another tab into a tab that was sitting on the picker. It now
+  runs once, so a second tab's Start is refused with the reattach offer it
+  was designed to get.
 - `anyio` 4.15.1 (two published advisories); both dependency audits clean.
 
 ### Release tooling