fix(persistence): derive SCHEMA_VERSION from migrations; unbreak the red suite (#140)

* fix(persistence): derive SCHEMA_VERSION from the migrations directory

db.py hardcoded SCHEMA_VERSION = 26 while migrations/ had already reached
v29 (v27 dispatcher floor-drop counter, v28 mesh_observations, v29 IPAWS).
The migration runner globs the directory and applies every vN.sql it finds
regardless of the constant, so a fresh DB actually landed at 29 while the
constant claimed 26 -- a three-version drift that three tests were
correctly catching.

Derive it from the highest vN.sql present instead of bumping the literal,
so it cannot drift again the next time someone adds a migration. Falls back
to 0 if the directory is missing so import never fails; the migrations dir
sits alongside db.py and ships with the package (Dockerfile COPYs meshai/).

Adds a regression guard asserting the constant matches the highest
migration file, and updates three tests that hardcoded 26 as a literal.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

* test(tle): make TLE fixtures time-relative so they cannot expire

The ISS fixtures hardcoded epochs of 2026-06-30/07-01/07-02. tle_handler
sets STALE_DAYS = 14 and get_tle_by_norad() filters on epoch >= now - 14d,
so the fixtures silently aged out on 2026-07-02 and the tests began
failing -- a time bomb, not a regression.

Compute epochs relative to wall-clock now (base = now - 2d, +/-1d for
newer/older) with correct TLE epoch-field encoding and mod-10 checksum.
STALE_DAYS is untouched -- widening it in product code would have changed
production behavior to paper over a test bug.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

* test(fire-tracker): pin config + history db to tmp_path

load_config() defaults HistoryConfig.database to the relative path
"conversations.db", resolved against the process CWD, so every test calling
load_config() with no override shares one file for the whole session. The
conftest DB-isolation fixture only covers MESHAI_DB_PATH, not this.

Point both the config dir and the history database at the test's tmp_path.

NOTE: this does NOT resolve the order-dependent failure -- the test still
passes standalone and fails in a full run, so the polluting state lives
somewhere other than config/history. Left failing rather than weakened;
root cause still unidentified.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

---------

Co-authored-by: Matt Johnson <mj@k7zvx.com>
Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

work/tests/test_satpass_persisted_timer.py

@@ -99,9 +99,11 @@ def _ingest_envelope(norad_id=25544, observer="Boise", max_el=72.5,
 # ── schema / migration ───────────────────────────────────────────────
 
 def test_schema_version_is_current():
-    # Bumped to 26 by the generic-source migration (v26 generic_events); v24
-    # avalanche_events, v25 ducting_events; was 23 at native-satpass (v23).
-    assert SCHEMA_VERSION == 26
+    # SCHEMA_VERSION is derived from the highest vN.sql in migrations/, so
+    # this just guards against the derivation returning something bogus
+    # (e.g. 0, which would mean the migrations dir wasn't found). The v22
+    # migration (this file's focus) must always be <= the current version.
+    assert SCHEMA_VERSION >= 22
 
 
 def test_v22_migration_applies_and_adds_due_at_column(tmp_path, monkeypatch):
@@ -114,7 +116,7 @@ def test_v22_migration_applies_and_adds_due_at_column(tmp_path, monkeypatch):
     close_thread_connection()
     conn = init_db()
     row = conn.execute("SELECT value FROM schema_meta WHERE key='version'").fetchone()
-    assert int(row["value"]) == 26
+    assert int(row["value"]) == SCHEMA_VERSION
     cols = {r["name"] for r in conn.execute("PRAGMA table_info(satpass_pending)")}
     assert "due_at" in cols
     close_thread_connection()