docs: clarify that ONE inbound SIP Trunk covers every Anveo DID

The step 4 heading said "once per DID" and the intro said steps 3-7 repeat
per DID, both of which overstate the work. The body already noted the trunk
could be reused, but the heading is what gets read first - and it actively
misleads toward creating one trunk object per number.

One inbound SIP Trunk serves the whole account: the $[E164]$ placeholder is
substituted with each DID's own number at call time, and the Asterisk side
matches whatever arrives via _X. and resolves it through
pstn-personal-dids.conf. Same for the outbound Service Trunk in step 3,
which the body already flagged as skippable for DIDs 2+.

Rewrites the heading, adds an explicit up-front note on why one suffices,
and corrects the intro to name which steps actually repeat per number.

docs/anveo-direct-setup-guide.md

@@ -2,9 +2,14 @@
 
 This is the exact sequence that got a real Anveo Direct DID working end to
 end (both outbound and inbound) with `asterisk-digital-ocean.sh` +
-`pstn-trunk.sh`, confirmed live on a real droplet. Follow it in order for
-each additional number — steps 1–2 are one-time account setup; steps
-3–7 repeat per DID.
+`pstn-trunk.sh`, confirmed live on a real droplet.
+
+**Steps 1, 3 and 4 are one-time account setup** — the outbound Service
+Trunk (step 3) and the inbound SIP Trunk (step 4) each cover every DID on
+the account, no matter how many you add. **Only steps 2, 4.5, 6 and 7
+repeat per number**: order the DID, point it at the existing inbound trunk
+(skippable entirely if you set the account default in step 4.6), assign it
+in the dashboard, and test.
 
 ## 0. Prerequisites
 
@@ -91,7 +96,7 @@ catch-all entry (prefix `1`); a few specific area codes have their own
 slightly different override rates, and Virgin Islands is billed
 separately/higher (~$0.02/min) despite looking like a normal US number.
 
-## 4. Create the SIP Trunk (inbound forwarding) — once per DID
+## 4. Create the SIP Trunk (inbound forwarding) — ONE covers every DID
 
 Anveo has **two unrelated "trunk" concepts** — don't confuse them:
 - The **Outbound Service Trunk** from step 3 handles calls *out*.
@@ -99,11 +104,20 @@ Anveo has **two unrelated "trunk" concepts** — don't confuse them:
   routing objects live) handles calls *in* — this is what actually
   populates a DID's "Destination SIP Trunk" dropdown.
 
-For **each DID**, create one of these:
+**You only need ONE of these for the whole account**, no matter how many
+DIDs you have. The `$[E164]$` placeholder in step 2 is what makes it
+reusable — Anveo substitutes each DID's own number at call time, so the
+same trunk object forwards `15551111111@IP:5060` for one DID and
+`15552222222@IP:5060` for another. The Asterisk side matches whatever
+arrives (`_X.` in `[from-pstn-trunk]`) and looks it up in
+`pstn-personal-dids.conf` to decide who rings. Creating one per DID is
+possible but pointless unless different DIDs need to forward to genuinely
+different destinations.
 
-1. **Trunk Name**: any label (e.g. `asterisk-do-inbound`) — can reuse the
-   same one for multiple DIDs if you want them all forwarding the same
-   way, or make one per DID for clarity.
+Create it once (steps 1–4), then per DID only step 5 applies — or set the
+account default in step 6 and skip even that:
+
+1. **Trunk Name**: any label (e.g. `asterisk-do-inbound`).
 2. **Primary**: type **SIP URI**, value:
    ```
    $[E164]$@<this box's public IP>:5060
@@ -115,12 +129,13 @@ For **each DID**, create one of these:
    in the actual INVITE Anveo sends.
 3. **Failover**: leave blank.
 4. Save.
-5. Go to the DID's own **Call Options** tab → set **Destination SIP
-   Trunk** to this new SIP Trunk object (not the Outbound Service Trunk)
+5. **Per DID**: go to that DID's **Call Options** tab → set **Destination
+   SIP Trunk** to this SIP Trunk object (not the Outbound Service Trunk)
    → Save.
-6. **Optional, recommended once you're adding more DIDs**: Account
+6. **Recommended if you have more than one or two DIDs**: Account
    Options → Service Defaults → set **Default Destination Trunk** to this
-   SIP Trunk, so future DIDs auto-route here without repeating step 5.
+   SIP Trunk. New DIDs then auto-route here and step 5 becomes unnecessary
+   entirely.
 
 ## 5. Configure the droplet