Release v0.51.295 — stage-3739/3742 (model-pick revert fix #3739 + session-status revert #3742) (#3743)

* fix: honor explicit model pick, suppress silent revert on cross-family selection (#3737)

When a user changes the model in the composer dropdown and sends,
_resolve_compatible_session_model_state previously had no way to
distinguish an explicit user pick from stale session state. The
profile-aware branch (v0.51.290, PR #3448) and the legacy block
both rewrote bare cross-family models to the profile default, and
the client unconditionally applied effective_model — silently
discarding the user's choice.

Backend: accept explicit_model_pick flag (default False) on
_resolve_compatible_session_model_state. Guard both the
profile-aware branch (routes.py:2024) and the legacy block
(routes.py:2124) to skip cross-provider normalization when set.
_handle_chat_start extracts the flag and passes it through.

Frontend: consult _readPendingSessionModel (sessionStorage, 10-min
window) to detect explicit picks and include the flag. Add a toast
as defense-in-depth when the server still returns effective_model.

Closes #3737

* fix: tighten explicit-pick detection and add regression tests (#3737)

Greptile P2-1: compare model_provider in pending pick detection,
not just model name, to avoid false-positive flag when the
session provider changes between pick and send.

Greptile P2-2: only show the defense-in-depth toast when an
explicit pick was actually overridden — stale-session
normalizations are expected behavior and should be silent.

Add two regression tests for the profile-branch guard:
- explicit_model_pick=True → cross-family model survives
- explicit_model_pick=False → existing normalization preserved

* revert(sidebar): remove manual session status labels (#3570)

The manual per-session status labels (Todo / In Progress / Done) added in
v0.51.284 (#3570) stored state only in browser localStorage keyed by session
id, with no server-side backing — so labels did not persist across browsers
or devices (a user who labeled sessions on one machine saw none after moving
to a laptop). They also rendered as three flat top-level entries in the
session context menu, crowding the root menu.

Per maintainer decision, remove the feature entirely for now. It can be
reintroduced later with proper server-side persistence and a less intrusive
menu treatment.

Removes:
- JS state/cycle helpers + SESSION_MANUAL_STATUS_KEY (static/sessions.js)
- context-menu status entries + sidebar status badge render
- .session-manual-status* CSS (static/style.css)
- session_status_* locale strings across all locales (static/i18n.js)

Full suite: 8084 passed, 0 failed. ESLint runtime gate: clean.

reverts #3570

* fix(#3737): keep explicit-pick marker until send consumes it (Codex catch)

Codex found the explicit_model_pick flag never engaged in the normal flow: boot.js
modelSelect.onchange cleared the pending-pick marker right after /api/session/update,
so by the time send() ran _readPendingSessionModel returned null, _explicitPick was
false, and the server's profile-provider branch still reverted the cross-family pick
(the exact #3737 bug). The flag only worked in the rare race where send beat the
session-update round-trip.

Fix (Codex prescription): do NOT clear the marker in onchange; clear it in send()
immediately after reading a matching pending pick, so it's consumed for that send only.
onchange still RECORDS the pick (_rememberPendingSessionModel) — only the premature
clear is removed.

* test(#3737): lock client clear-timing wiring (onchange records, send consumes)

Static source guards for the Codex clear-timing fix: onchange must record the
pending pick and NOT clear it post-session-update; send() must consume (clear) it
only after reading a matching _explicitPick, and send the flag only when truthy.
Complements the author's resolver-level tests in test_provider_mismatch.py.

* test(#3737): realign refresh-persistence test to the moved pending-pick clear

The Codex clear-timing fix moved the pending-pick clear out of modelSelect.onchange
into send() (consume-on-send). test_model_selection_records_pending_state_before_async_session_update
asserted the OLD onchange-clears behavior (assert _clearPendingSessionModel in body).
Updated to assert the NEW correct behavior (onchange must NOT clear it — it survives to
send). The test's core refresh-survives invariant (marker recorded before the async
session-update; reapplied on load) is unchanged and still passes; only the stale
clear-location assertion is flipped. Not a regression-blessing: the refresh-survives
feature is intact, the marker lifecycle is more correct.

---------

Co-authored-by: John Doe <johndoe@example.com>
Co-authored-by: nesquena-hermes <[email protected]>

tests/test_provider_mismatch.py

@@ -1438,6 +1438,43 @@ def test_custom_namespace_model_always_preserved_on_custom_provider(monkeypatch)
     assert effective == "custom/my-local-llm"
 
 
+def test_explicit_pick_survives_profile_family_mismatch():
+    """When explicit_model_pick=True, a cross-family bare model survives
+    the profile-aware normalization instead of being rewritten to the
+    profile default (#3737)."""
+    import api.routes as routes
+
+    effective, provider, changed = routes._resolve_compatible_session_model_state(
+        "gpt-5.4-mini",
+        None,
+        profile_provider="anthropic",
+        profile_default_model="claude-sonnet-4",
+        explicit_model_pick=True,
+    )
+
+    assert changed is False, "explicit pick must not be normalized"
+    assert effective == "gpt-5.4-mini", "user's model must survive"
+    assert provider == "anthropic", "profile provider context preserved"
+
+
+def test_explicit_pick_false_allows_profile_family_normalization():
+    """Without explicit_model_pick, the same cross-family model IS rewritten
+    to the profile default (existing behavior, must not regress)."""
+    import api.routes as routes
+
+    effective, provider, changed = routes._resolve_compatible_session_model_state(
+        "gpt-5.4-mini",
+        None,
+        profile_provider="anthropic",
+        profile_default_model="claude-sonnet-4",
+        explicit_model_pick=False,
+    )
+
+    assert changed is True, "stale model must be normalized"
+    assert effective == "claude-sonnet-4", "rewritten to profile default"
+    assert provider == "anthropic", "profile provider context preserved"
+
+
 def test_stale_ui_js_does_not_inject_unavailable_option():
     """renderSession() must no longer inject a bare (unavailable) option into
     modelSelect when the session model is not in the provider list (#829).