docs: rephrase the vale warnings that have a better wording

Words the alex and Microsoft styles flag where a plainer one reads as well:
disabled/special/invalid as a state, primitive, trap, hang, several, click,
first-person FAQ questions, hyphenated adverb pairs. Left as they are: Let's
Encrypt, quoted UI labels and phrases, the generated forge CLI reference, and
the middle-click gesture.

docs/process/conventions.md

@@ -88,7 +88,7 @@ namespace, not the wire surface.
 
 ## Recipient sentinels
 
-The broker reserves a few recipient names, which have special
+The broker reserves a few recipient names, which have a fixed
 meaning that ordinary agent labels can never collide with — agent
 name validation rejects any character outside `[a-z0-9_-]`, so the
 angle-bracket and asterisk shapes below are structurally safe.

docs/process/gotchas.md

@@ -156,7 +156,7 @@ an input only because a docs tree has no runtime dependencies.
 
 <!-- vale write-good.Passive = NO -->
 
-The `storePath` trap is worth spelling out, because it's not confined
+The `storePath` pitfall is worth spelling out, because it's not confined
 to options the operator writes: **any** option of type `package` fed a
 store-path _string_ coerces through `lib.toDerivation`, i.e.
 `builtins.storePath`. `environment.systemPackages` and
@@ -465,7 +465,7 @@ connects to the compositor at `127.0.0.1:<vnc_port>`.
   Same reasoning as the best-effort oneshots in `docs/process/conventions.md`.
 - **`[core] idle-time=0`**: disables weston's 300-second idle
   timeout. Without it the VNC desktop fades to black and
-  desktop-shell shows its click-to-unlock screen — useless for an
+  desktop-shell shows its unlock screen — useless for an
   agent desktop viewed over `/screen`. `idle-time=0` updates the
   idle timer with a 0ms delay, which
   `wl_event_source_timer_update` treats as "disarm," so the