feat(2-E.5): single-source-of-truth stream registry

Eliminates the duplication that has been hand-bumped through PRs B, C, D, E.
Adding a stream is now one StreamEntry in src/central/streams.py + one
migration row in config.streams. supervisor STREAM_SUBJECTS / archive
STREAMS / gui DASHBOARD_STREAMS all derive at import time. No drift
possible because there is one source.

Pure refactor; no behavior change. Runtime verified: derived structures
are byte-equivalent to the previous literal definitions.

src/central/streams.py (new):
  @dataclass(frozen=True)
  class StreamEntry:
      name: str
      subject_filter: str
      event_bearing: bool = True   # archive consumes from this stream
      dashboard: bool = True       # GUI dashboard surfaces this stream

  STREAMS: list[StreamEntry] = [
      StreamEntry("CENTRAL_WX",       "central.wx.>"),
      StreamEntry("CENTRAL_FIRE",     "central.fire.>"),
      StreamEntry("CENTRAL_QUAKE",    "central.quake.>"),
      StreamEntry("CENTRAL_SPACE",    "central.space.>"),
      StreamEntry("CENTRAL_DISASTER", "central.disaster.>"),
      StreamEntry("CENTRAL_META",     "central.meta.>", event_bearing=False),
  ]

Consumers derive:
  supervisor.STREAM_SUBJECTS = {s.name: [s.subject_filter] for s in STREAMS}
    (includes META: supervisor must create every stream in JetStream)
  archive.STREAMS = [(s.name, s.subject_filter) for s in STREAMS if s.event_bearing]
    (excludes META: status messages, not events)
  gui.DASHBOARD_STREAMS = [s.name for s in STREAMS if s.dashboard]

To resolve the name collision between the registry STREAMS and the
existing archive.STREAMS public symbol, archive.py imports the registry
under an alias: from central.streams import STREAMS as STREAM_REGISTRY.
The archives STREAMS surface (the tuple-list) is unchanged for callers.
Same alias used in supervisor.py and gui/routes.py for symmetry.

Migration files unchanged. config.streams keeps seeding retention/bytes --
operator-tunable ops state, separate SoT from the structural mapping.

Tests:
  Dropped from test_archive_multi_stream.py (7, all tautological vs. registry):
    test_streams_list_has_five_entries (magic-number count)
    test_streams_contains_central_wx / fire / quake / space / disaster
    test_streams_excludes_central_meta
  Dropped from test_dashboard.py:
    `assert len(streams) == 6` line inside test_single_stream_failure_doesnt_crash_card
    (the test itself stays; only the magic-number assertion is removed)
  Added in test_stream_registry.py (8 invariant tests):
    test_stream_names_unique
    test_subject_filters_unique
    test_subject_filter_central_prefix_wildcard
    test_meta_is_only_non_event_bearing
    test_supervisor_stream_subjects_includes_meta
    test_supervisor_stream_subjects_includes_all
    test_archive_streams_excludes_non_event_bearing
    test_dashboard_streams_matches_dashboard_flag

The new tests assert properties (uniqueness, format, derivation correctness),
not literals. Future stream additions need zero new test code -- every
invariant automatically covers them.

Note: test file named tests/test_stream_registry.py (not test_streams.py)
to avoid colliding with the pre-existing tests/test_streams.py, which
covers the GUI streams-management page.

Full suite: 427 passed (was 426 on main: -7 dropped + 8 added).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/central/archive.py

@@ -19,15 +19,11 @@ from nats.js.api import ConsumerConfig, DeliverPolicy, AckPolicy
 from nats.js.errors import NotFoundError
 
 from central.bootstrap_config import get_settings
+from central.streams import STREAMS as STREAM_REGISTRY
 
-# Event-bearing streams to consume (skip CENTRAL_META - status messages only)
-STREAMS = [
-    ("CENTRAL_WX", "central.wx.>"),
-    ("CENTRAL_FIRE", "central.fire.>"),
-    ("CENTRAL_QUAKE", "central.quake.>"),
-    ("CENTRAL_SPACE", "central.space.>"),
-    ("CENTRAL_DISASTER", "central.disaster.>"),
-]
+# Event-bearing streams to consume -- derived from the registry's event_bearing flag.
+# CENTRAL_META is excluded because it carries status messages, not events.
+STREAMS = [(s.name, s.subject_filter) for s in STREAM_REGISTRY if s.event_bearing]
 
 BATCH_SIZE = 100
 FETCH_TIMEOUT = 5.0

src/central/gui/routes.py

@@ -49,6 +49,7 @@ from functools import cache
 from central.gui.db import get_pool
 from central.gui.form_descriptors import describe_fields, FieldDescriptor
 from central.adapter_discovery import discover_adapters
+from central.streams import STREAMS as STREAM_REGISTRY
 from pydantic import ValidationError
 
 @cache
@@ -63,8 +64,8 @@ def _adapter_classes() -> dict:
 
 router = APIRouter()
 
-# Streams to display on dashboard
-DASHBOARD_STREAMS = ["CENTRAL_WX", "CENTRAL_FIRE", "CENTRAL_QUAKE", "CENTRAL_SPACE", "CENTRAL_DISASTER", "CENTRAL_META"]
+# Streams to display on dashboard -- derived from the registry's dashboard flag.
+DASHBOARD_STREAMS = [s.name for s in STREAM_REGISTRY if s.dashboard]
 
 # Email validation regex (simple but effective)
 ALIAS_REGEX = re.compile(r"^[a-zA-Z0-9_]+$")

src/central/streams.py

@@ -0,0 +1,32 @@
+"""Stream registry — single source of truth for NATS JetStream stream definitions.
+
+Subject-filter mappings live in code (structural; change only when code changes).
+Retention / max_bytes live in config.streams (operator-tunable; ops state).
+
+Adding a stream: one StreamEntry below + one migration row that seeds
+config.streams. supervisor STREAM_SUBJECTS / archive STREAMS / gui DASHBOARD_STREAMS
+all derive automatically.
+"""
+
+from dataclasses import dataclass
+
+
+@dataclass(frozen=True)
+class StreamEntry:
+    name: str
+    subject_filter: str
+    event_bearing: bool = True
+    """Whether central-archive consumes events from this stream into the events table.
+    False for status-only streams (CENTRAL_META) that the archive intentionally skips."""
+    dashboard: bool = True
+    """Whether the GUI dashboard surfaces this stream's stats card."""
+
+
+STREAMS: list[StreamEntry] = [
+    StreamEntry("CENTRAL_WX",       "central.wx.>"),
+    StreamEntry("CENTRAL_FIRE",     "central.fire.>"),
+    StreamEntry("CENTRAL_QUAKE",    "central.quake.>"),
+    StreamEntry("CENTRAL_SPACE",    "central.space.>"),
+    StreamEntry("CENTRAL_DISASTER", "central.disaster.>"),
+    StreamEntry("CENTRAL_META",     "central.meta.>", event_bearing=False),
+]

src/central/supervisor.py

@@ -21,17 +21,12 @@ from central.config_source import ConfigSource, DbConfigSource
 from central.config_store import ConfigStore
 from central.bootstrap_config import get_settings
 from central.stream_manager import StreamManager
+from central.streams import STREAMS as STREAM_REGISTRY
 CURSOR_DB_PATH = Path("/var/lib/central/cursors.db")
 
-# Stream subject mappings
-STREAM_SUBJECTS = {
-    "CENTRAL_WX": ["central.wx.>"],
-    "CENTRAL_META": ["central.meta.>"],
-    "CENTRAL_FIRE": ["central.fire.>"],
-    "CENTRAL_QUAKE": ["central.quake.>"],
-    "CENTRAL_SPACE": ["central.space.>"],
-    "CENTRAL_DISASTER": ["central.disaster.>"],
-}
+# Stream subject mappings -- derived from the registry; every stream is included
+# (META too: supervisor must create it in JetStream even though archive skips it).
+STREAM_SUBJECTS = {s.name: [s.subject_filter] for s in STREAM_REGISTRY}
 
 # Recompute interval for stream max_bytes (1 hour)
 STREAM_RECOMPUTE_INTERVAL_S = 3600