Stamp org_id everywhere and gate every route that leaked across tenants

The previous commit shipped Firestore rules that reference an org_id claim
nothing issues yet, and an org_id filter nothing writes yet - this is the
commit that makes both real. Backend half of SAAS_PLAN.md B2/B2b/B2c.

Data model: organizations/{org_id} and org_members/{uid} are new
collections (models.py OrganizationRecord/OrgMember). org_id is now an
Optional field on NodeRecord, SystemRecord, CallRecord, IncidentRecord,
AlertRule, and AlertEvent - optional because every existing document
predates it; scripts/backfill_org_id.py (written, not run - it touches
production Firestore and Firebase Auth claims) is what closes that gap
later. plan_id/subscription_status/stripe_* on OrganizationRecord are
deliberately None: no billing or pricing model has been decided, so this is
a seam, not a promise. app/internal/tenancy.py holds FOUNDING_ORG_ID, the
org every pre-tenancy document and every legacy enrollment path resolves
into.

Where org_id comes from, end to end: a customer's node enrolls with a
per-org token (new enrollment_tokens/{token_hash} collection, minted via
POST /org/enrollment-tokens - new routers/org.py) instead of the old
fleet-wide ENROLLMENT_TOKEN, which still works as a fallback that resolves
to FOUNDING_ORG_ID so an already-deployed node's .env doesn't start failing
today. The node's org_id then flows onto every call it produces
(mqtt_handler.py's call_start/call_end, upload.py's /upload handler all
resolve it from the node doc), and onto every incident correlated from
those calls (incident_correlator.py's _create_incident/_create_master_incident).

That last one is the part that isn't just a read filter: _build_context's
`all_active = collection_list("incidents", status="active")` fed every
correlation candidate - fast-path talkgroup match, unit-continuity,
disambiguation - from the entire incidents collection, unscoped. Without
scoping it to the call's own org_id, a call from org A could link into an
incident org B already owns, which is a cross-tenant data merge at
correlation time, not just an over-broad read. Same shape of bug in
alerter.py: rule matching pulled every enabled alert_rule regardless of
org, so org A's keyword rule could fire (and POST org A's Discord webhook)
on org B's radio traffic. Both now resolve org_id from the call doc itself
rather than threading a new parameter through every caller.

Every list/get route gained org scoping via a new resolve_caller_org_id()
helper in internal/auth.py, which handles the three credential shapes those
routes accept (service key, node api_key, Firebase user) uniformly and
returns None (unrestricted) for the service key and platform admins -
preserving today's single-org behaviour exactly while closing the leak for
everyone else: GET /nodes, /systems, /calls, /incidents, /alerts,
/alert-rules. Write routes for nodes/systems (approve, create, delete, etc.)
deliberately stay platform-admin-only for now rather than being loosened to
org-owner/operator - that's a real gap called out in SAAS_PLAN.md 2.4's
"should be" column, but it's a separate authorization redesign the 12-item
build order doesn't actually enumerate, and doing it half-considered here
risked being exactly the "half-applied filter is worse than none" failure
mode the plan warns about. Today's founding org keeps working unchanged;
loosening node/system management to org owners is follow-up work, flagged
rather than guessed at.

Also closed the four spend/access-attack routes SAAS_PLAN.md B2c called out
by file and line: POST /calls/{id}/reprocess is now admin-only (was any
signed-in viewer looping the Whisper+Gemini pipeline for free - DEFERRED.md
had this as a live, independent-of-SaaS exploit) plus a per-call rate
limiter as a second guard; POST /alerts/{id}/acknowledge now checks the
alert's org_id; GET /admin/features moved from require_firebase_token to
require_admin_token; and trips.py's four unauthenticated mutation routes
(create_trip, update_trip_tags, create_event, update_event) are now
restricted to the founding org (or the bot's service key, or a platform
admin) - trips has no org_id of its own and isn't getting one, since
[[trips-feature-intentional]] says it's an internal utility riding along on
this stack, not a tenant-scoped product surface.

New public-but-scoped seam: POST /auth/signup (routers/links.py, alongside
the existing /auth/link* routes) provisions an organizations doc and an
owner org_members doc for a just-created Firebase user, then sets their
org_id/org_role claims - idempotent, so a double-submit doesn't create two
orgs. This is the only route that turns "has a Firebase account" into "can
read anything," which is what the frontend AuthProvider no-claim guard
(next commit) is built around.

Also new: GET/PATCH /org for the organization profile (closes the disabled
"Save changes" button noted in DEFERRED.md - there was no organizations
concept to save into before this), and POST /waitlist (public, source-IP
rate-limited, not coupled to any plan or tier - the commercial model is
still an open decision per SAAS_PLAN.md section 6).

Verified: all touched files py_compile clean; c2-core pytest is 69
passed / 10 failed, matching the documented pre-existing baseline exactly
(DEFERRED.md - mqtt_handler/node_sweeper test-vs-code drift, unrelated to
this change) - no new failures. flake8 --max-line-length=120 shows no new
violations in any touched file (checked each new E501/E221/E30x against
`git diff` to confirm it predates this commit); c2-core has no CI lint gate
regardless (CLAUDE.md - flake8 only runs in Client CI).

No new environment variables. Firestore composite indexes for the queries
this introduces were already shipped in the previous commit
(infra/firestore/firestore.indexes.json).

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

drb-c2-core/app/models.py

@@ -3,6 +3,50 @@ from typing import Optional, List, Dict, Any
 from datetime import datetime
 
 
+# ---------------------------------------------------------------------------
+# Organizations — the tenant boundary. See SAAS_PLAN.md B2 and
+# app/internal/auth.py's require_org(). plan_id/subscription_status and the
+# stripe_* fields are deliberately inert (None) here: no billing model has
+# been decided yet (participation-based / reciprocal access, not per-seat
+# SaaS — see the note on FOUNDING_ORG_ID in app/internal/tenancy.py), so this
+# is just the seam a future billing pass would write into, not a promise
+# about what that pass looks like.
+# ---------------------------------------------------------------------------
+
+class OrganizationRecord(BaseModel):
+    org_id: str
+    name: str
+    created_at: datetime
+    created_by_uid: str
+    plan_id: Optional[str] = None
+    subscription_status: Optional[str] = None
+    stripe_customer_id: Optional[str] = None
+    stripe_subscription_id: Optional[str] = None
+    current_period_end: Optional[datetime] = None
+    seat_limit: Optional[int] = None
+    node_limit: Optional[int] = None
+    retention_days: Optional[int] = None
+
+
+class OrgMember(BaseModel):
+    uid: str
+    org_id: str
+    org_role: str  # "owner" | "member"
+    email: Optional[str] = None
+    added_at: datetime
+
+
+class EnrollmentTokenRecord(BaseModel):
+    """Firestore doc id is the SHA-256 hash of the raw token — see
+    routers/enrollment.py's _hash_secret pattern (pickup_secret_hash)."""
+    org_id: str
+    label: str
+    created_at: datetime
+    created_by_uid: str
+    revoked: bool = False
+    uses: int = 0
+
+
 # ---------------------------------------------------------------------------
 # Nodes
 # ---------------------------------------------------------------------------
@@ -10,6 +54,7 @@ from datetime import datetime
 class NodeRecord(BaseModel):
     node_id: str
     name: str
+    org_id: Optional[str] = None     # stamped at enrollment; None only on pre-tenancy docs awaiting backfill
     lat: float = 0.0
     lon: float = 0.0
     status: str = "offline"          # online / offline / recording / unconfigured
@@ -35,6 +80,7 @@ class CommandPayload(BaseModel):
 
 class SystemRecord(BaseModel):
     system_id: str
+    org_id: Optional[str] = None
     name: str
     type: str                        # P25 / DMR / NBFM
     config: Dict[str, Any] = {}     # OP25-compatible config blob
@@ -55,6 +101,7 @@ class SystemCreate(BaseModel):
 class CallRecord(BaseModel):
     call_id: str
     node_id: str
+    org_id: Optional[str] = None  # inherited from the node at call_start/upload — see internal/mqtt_handler.py
     system_id: Optional[str] = None
     talkgroup_id: Optional[int] = None
     talkgroup_name: Optional[str] = None
@@ -78,6 +125,7 @@ class CallRecord(BaseModel):
 
 class IncidentRecord(BaseModel):
     incident_id: str
+    org_id: Optional[str] = None  # inherited from the calls that created it — see internal/incident_correlator.py
     title: Optional[str] = None
     type: Optional[str] = None         # fire / police / ems / etc.
     status: str = "active"             # active / resolved
@@ -114,6 +162,7 @@ class IncidentUpdate(BaseModel):
 
 class AlertRule(BaseModel):
     rule_id: Optional[str] = None
+    org_id: Optional[str] = None
     name: str
     keywords: List[str] = []
     talkgroup_ids: List[int] = []
@@ -131,6 +180,7 @@ class AlertRuleUpdate(BaseModel):
 
 class AlertEvent(BaseModel):
     alert_id: Optional[str] = None
+    org_id: Optional[str] = None
     rule_id: str
     rule_name: str
     call_id: str