docs: fix genuine passive-voice hits in getting-started/setup.md

First doc-directory of hyperhive#4042's Passive pass (705+ hits across
docs/, genuinely mixed unlike TooWordy -- needs a real per-hit read,
not a dictionary shortcut, so this is going doc-directory by
doc-directory in small PRs, per the plan posted on the issue).

Read all 13 flagged hits in this file in context, not just the flagged
word. 3 were genuine catches with a real active-voice improvement and
a nameable actor:

- "the human operator's own forge/matrix account is created via swarm
  SSO" -> "swarm SSO creates the human operator's own forge/matrix
  account" (x2, identical sentence shape for both accounts) -- swarm
  SSO is a nameable, specific actor already named later in the same
  sentence, so naming it as the subject too is strictly clearer, not
  just different.
- "Do this before anything is pointed at it" -> "Do this before you
  point anything at it" -- matches the doc's own established
  second-person imperative voice used throughout ("Do this", "Put the
  token's value", "Delete the file"); the passive here was the odd one
  out, not the house style.

The other 10 are legitimate passives, left alone:
- Generic/unspecified-actor statements ("is needed", "is bound", "is
  issued", "been run") where forcing a subject would either invent an
  actor the doc never established or read worse than the original.
- Security/architecture invariants ("No forge admin token is stored in
  any agent state dir", "Telemetry ingest is authenticated per hive")
  -- "No X is Y" / "X is Y" is the standard idiom for a guarantee
  statement in security docs, not a clarity problem to fix.
- "operator-only surfaces ... are gated on that group" -- borderline
  (could name the group as subject), judged idiomatic access-control
  phrasing rather than genuinely clearer active, but flagged as the
  closest call in this batch.

Verified: vale docs/getting-started/setup.md before/after -- 13 -> 10
write-good.Passive hits (exactly the 3 rewritten), the pre-existing
unrelated alex.Suicide hit on "hang" (line 51, untouched) still
present and correctly out of scope for this pass.

docs/getting-started/setup.md

@@ -31,7 +31,7 @@ hivectl forge create-user ruth
 # forge accounts auto-provisioned — nothing to run here for them.
 ```
 
-The human operator's own forge account is created via swarm SSO instead of
+Swarm SSO creates the human operator's own forge account instead of
 a manual `hivectl` step — see step 3 (`swarmctl user add`).
 
 ### 2 · Gateway (HTTP Basic auth)
@@ -49,7 +49,7 @@ hivectl gateway list-users
 ⚠️ **A sealed store still answers.** OpenBao starts uninitialised and
 sealed, so the container is up and the port responds while every read
 times out — the failure looks like a hang, not like a store that was
-never initialised. Do this before anything is pointed at it.
+never initialised. Do this before you point anything at it.
 
 ```bash
 # On the host that RUNS the store, once.
@@ -192,7 +192,7 @@ hivectl matrix invite @mara:yourserver --room '#hive-chat:yourserver'
 hivectl matrix promote-user mara
 ```
 
-The human operator's own matrix account is created via swarm SSO instead of
+Swarm SSO creates the human operator's own matrix account instead of
 a manual `hivectl` step — see step 3 (`swarmctl user add`).
 
 ### 7 · Spawn sub-agents