Realign processor stream-name default to telemetry:teltonika

Stage discovered the wrong default at runtime: tcp-ingestion's compiled
default REDIS_TELEMETRY_STREAM is 'telemetry:teltonika' but processor's
was 'telemetry:t', so the two services were talking past each other —
tcp-ingestion publishing to one stream, processor reading another empty
one. The deploy stack now pins both to the same value via a shared env
var, but the processor's compiled default should also match so local
development and the integration test stay aligned with reality.

Changes:
- src/config/load.ts — default changed to 'telemetry:teltonika'
- .env.example — same
- test/config.test.ts — default-value assertion updated
- planning docs (ROADMAP, phase-1 README, tasks 03/08/10, phase-3 README) —
  occurrences of 'telemetry:t' replaced with 'telemetry:teltonika'

The deploy stack remains the single source of truth via the shared
REDIS_TELEMETRY_STREAM env var. Compiled defaults are belt-and-braces.

src/config/load.ts

@@ -44,7 +44,7 @@ const ConfigSchema = z.object({
   POSTGRES_URL: urlWithProtocol(['postgres', 'postgresql']),
 
   // Redis stream / group config — must match tcp-ingestion's output stream
-  REDIS_TELEMETRY_STREAM: z.string().min(1).default('telemetry:t'),
+  REDIS_TELEMETRY_STREAM: z.string().min(1).default('telemetry:teltonika'),
   REDIS_CONSUMER_GROUP: z.string().min(1).default('processor'),
   // Consumer name defaults to INSTANCE_ID; resolved after schema parse (see below)
   REDIS_CONSUMER_NAME: z.string().min(1).optional(),