test: make tests/ mirror the source tree; drop issue numbers from filenames

`scripts/run_tests.sh tests/<dir>/` is how a change gets its regression
coverage run, so a test filed under the wrong directory is a test nobody
runs when that code changes. Two kinds of drift had accumulated.

Parallel directories for one source package, folded into the mirror:
  tests/acp        -> tests/acp_adapter   (its __init__/conftest move with it)
  tests/cli        -> tests/hermes_cli    (prompt_toolkit fixture merged into
                                           hermes_cli/conftest.py)
  tests/run_agent  -> tests/agent         (backoff fixture becomes
                                           agent/conftest.py)
  tests/relay      -> tests/gateway/relay
  tests/state      -> tests/hermes_state

246 loose files at tests/ root, routed by the package they import/patch:
hermes_cli, hermes_state, agent, gateway, tools, plugins, tui_gateway, cron.
Installer and desktop-update script tests go to tests/scripts/{install,
desktop_update}/. 43 tests of root-level modules (batch_runner, utils,
hermes_constants, packaging) stay at the root.

Filenames drop their issue numbers (95 files: test_89315_x.py -> test_x.py);
the number stays in the module docstring where it has context.

Collisions: test_cli_skin_integration.py existed in both tests/ and tests/cli
with different subsets — merged into one (10 tests, all kept);
run_agent/test_pre_compress_memory_context.py -> agent/..._handoff.py;
tests/test_account_usage.py -> agent/test_account_usage_fetch.py;
tests/test_web_server.py -> hermes_cli/test_web_server_ws_ping.py.
Deleted: test_minisweagent_path.py (empty since PR #2804),
test_model_picker_scroll.py (tested a private copy of the logic, imported
nothing), test_process_loop_event_loop_warning.py (asserted asyncio behaviour,
imported nothing from Hermes).

Repo-root path arithmetic (Path(__file__).parents[N], dirname chains) is
bumped for the 202 files that changed depth and verified by evaluating every
such expression against the new location. classify_changes' desktop-updater
lane prefix, tests-os.yml's ignore glob and every in-tree path comment follow
the moves. tests/test_tests_tree_layout.py keeps the tree from drifting back.

tests/test_session_db_profile_stamp.py

@@ -1,137 +0,0 @@
-"""SessionDB stamps its own store's profile onto new session rows (#99222).
-
-Every profile-tree ``state.db`` belongs to exactly one profile, so when a
-creation path passes no ``profile_name`` the store derives its own owner
-instead of persisting NULL. NULL rows minted after the one-shot #94724
-legacy-owner backfill stayed NULL forever and vanished from profile-keyed
-consumers (desktop sidebar scope matching, ``@session:<profile>/<id>`` deep
-links). Stores outside the profile tree must NOT guess — they keep NULL.
-"""
-
-import sqlite3
-
-import pytest
-
-import hermes_state
-from hermes_state import SessionDB
-
-
-@pytest.fixture
-def hermes_root(tmp_path, monkeypatch):
-    root = tmp_path / "hermes"
-    (root / "profiles" / "workprof").mkdir(parents=True)
-    monkeypatch.setenv("HERMES_HOME", str(root))
-    # get_default_hermes_root memoizes on (native_home, env) — the env change
-    # invalidates the memo by itself, but re-point DEFAULT_DB_PATH so any
-    # default-constructed SessionDB in the module under test stays sandboxed.
-    monkeypatch.setattr(hermes_state, "DEFAULT_DB_PATH", root / "state.db")
-    return root
-
-
-def _profile_of(db_path, session_id):
-    conn = sqlite3.connect(db_path)
-    try:
-        row = conn.execute(
-            "SELECT profile_name FROM sessions WHERE id = ?", (session_id,)
-        ).fetchone()
-        return row[0] if row else None
-    finally:
-        conn.close()
-
-
-def test_default_store_stamps_default(hermes_root):
-    db = SessionDB(db_path=hermes_root / "state.db")
-    try:
-        db.create_session("s_default", source="cli")
-    finally:
-        db.close()
-    assert _profile_of(hermes_root / "state.db", "s_default") == "default"
-
-
-def test_named_profile_store_stamps_own_name(hermes_root):
-    db_path = hermes_root / "profiles" / "workprof" / "state.db"
-    db = SessionDB(db_path=db_path)
-    try:
-        db.create_session("s_prof", source="desktop")
-    finally:
-        db.close()
-    assert _profile_of(db_path, "s_prof") == "workprof"
-
-
-def test_explicit_profile_name_wins(hermes_root):
-    db = SessionDB(db_path=hermes_root / "state.db")
-    try:
-        db.create_session("s_explicit", source="cli", profile_name="llm-wiki")
-    finally:
-        db.close()
-    assert _profile_of(hermes_root / "state.db", "s_explicit") == "llm-wiki"
-
-
-def test_store_outside_profile_tree_never_guesses(hermes_root, tmp_path):
-    db_path = tmp_path / "elsewhere" / "state.db"
-    db_path.parent.mkdir()
-    db = SessionDB(db_path=db_path)
-    try:
-        db.create_session("s_outside", source="cli")
-    finally:
-        db.close()
-    assert _profile_of(db_path, "s_outside") is None
-
-
-def test_compression_child_of_null_parent_is_stamped(hermes_root):
-    db_path = hermes_root / "state.db"
-    db = SessionDB(db_path=db_path)
-    try:
-        db.create_session("s_parent", source="cli")
-        # Simulate a legacy pre-ownership parent row.
-        conn = sqlite3.connect(db_path)
-        conn.execute(
-            "UPDATE sessions SET profile_name = NULL WHERE id = ?", ("s_parent",)
-        )
-        conn.commit()
-        conn.close()
-        db.publish_compression_child(
-            parent_session_id="s_parent",
-            child_session_id="s_child",
-            source="cli",
-            messages=[{"role": "user", "content": "hi"}],
-            require_compression_lease=False,
-        )
-    finally:
-        db.close()
-    assert _profile_of(db_path, "s_child") == "default"
-
-
-def test_peer_self_heal_insert_is_stamped(hermes_root):
-    db_path = hermes_root / "state.db"
-    db = SessionDB(db_path=db_path)
-    try:
-        # No prior row: the #82616 self-heal INSERT creates it.
-        db.record_gateway_session_peer(
-            "s_selfheal",
-            source="telegram",
-            user_id="u1",
-            session_key="k1",
-            chat_id="c1",
-        )
-    finally:
-        db.close()
-    assert _profile_of(db_path, "s_selfheal") == "default"
-
-
-def test_legacy_backfill_still_targets_only_null(hermes_root):
-    """The one-shot #94724 backfill contract is unchanged: explicit owners are
-    never overwritten, and new rows no longer regenerate its input."""
-    db_path = hermes_root / "state.db"
-    db = SessionDB(db_path=db_path)
-    try:
-        db.create_session("s_new", source="cli")
-        conn = sqlite3.connect(db_path)
-        conn.execute("UPDATE sessions SET profile_name = NULL WHERE id = 's_new'")
-        conn.commit()
-        conn.close()
-        assert db.backfill_null_session_profiles("workprof") == 1
-        assert db.backfill_null_session_profiles("workprof") == 0
-    finally:
-        db.close()
-    assert _profile_of(db_path, "s_new") == "workprof"