docs: fix write-good.So/ThereIs/Weasel lint findings

Fixes the "obvious ones first" slice of #4042 (mara: do the obvious
ones first) -- 81 hits across write-good.So, write-good.ThereIs, and
write-good.Weasel, all in docs/. Each is a genuine sentence rewrite
(lead with the real subject instead of "There is/are", drop a
sentence-initial "So ", replace a vague intensifier), not a blind
regex substitution -- read every hit in its real file context before
touching it.

3 of the 81 hits were in CI-generated CLI docs (docs/tools/{hivectl,
swarmctl,forge}-cli.md) -- fixed at the clap #[arg(...)]/doc-comment
source in hivectl/src/cli.rs, swarmctl/src/main.rs, and
hive-forge/src/verbs/repo_add_collaborator.rs, then regenerated via
each crate's `markdown-docs` subcommand so CI's freshness check stays
green.

Verified: fresh vale re-run shows 0 remaining So/ThereIs/Weasel hits
and no new hits introduced (983->982, exactly the one incidental fix
this pass also picked up at docs/scheduler/observability.md:48).
cargo fmt --check and clippy clean on the three touched crates.

Remaining write-good backlog (Passive: 726, TooWordy: 207) is
judgment-heavy and left for a follow-up slice of #4042, not bulk-
rewritten here.

docs/web-ui/dashboard.md

@@ -141,7 +141,7 @@ dirs; `POST /api/purge-tombstone/{name}`).
 ⚠️ **Not only *destroyed* agents.** Nothing records a destroy: every
 definition-side artifact (state subvolume, proposed + applied repos,
 meta registration, topology entry) is written by `Provision` *before*
-the container exists and survives `lifecycle::destroy`. So an agent
+the container exists and survives `lifecycle::destroy`. An agent
 part-way through a spawn is byte-identical on disk to a tombstone, and
 both are listed. The pane carries a standing warning to that effect, and
 the row badge says `offline` rather than `destroyed` — the absence of a
@@ -474,8 +474,8 @@ Both tables share the same visual shape: `.cap-table-wrap` /
 and its checkbox cells, where each checkbox carries `data-baseline` (its
 render-time state) and the row carries `data-agent` for dirty-tracking.
 
-**Saving — one button for the whole page.** There are no per-row save
-buttons. A single page-level `.perm-save-bar` with a **save all (N
+**Saving — one button for the whole page.** No per-row save
+buttons exist. A single page-level `.perm-save-bar` with a **save all (N
 agents)** button sits at the bottom of the pane, enabled only when some
 checkbox diverges from its baseline. Clicking it diffs every checkbox
 across *both* matrices and POSTs one batch to `POST /api/permissions` as
@@ -826,7 +826,7 @@ limited` (red, while the harness is parked after a 429), `needs
 login`, `needs update` — plus **one `◐ pending-state…` pill per
 active transient** (replaces buttons during operator-initiated
 start / stop / restart / rebuild / destroy). An agent can carry
-**several transients at once** — for example a lease-exempt `prebuild`
+**multiple transients at once** — for example a lease-exempt `prebuild`
 running alongside a `stop_for_update` on the same agent — and each
 renders as its own independent badge rather than being collapsed
 into one label, matching the existing multi-badge convention this
@@ -1337,8 +1337,8 @@ payload):
   every queue mutation (enqueue, state transition, dedup collapse,
   terminal-history trim). Unlike the snapshot events below it ships
   no state at all: the client re-fetches `GET /api/jobq/graph`, which
-  is where it reads the queue from cold too. There is no
-  `/api/state.rebuild_queue` — it went with the typed projection.
+  is where it reads the queue from cold too. No
+  `/api/state.rebuild_queue` exists — it went with the typed projection.
 - `schedules_changed` (seq, schedules: `Vec<WireSchedule>`) —
   full snapshot of all scheduled prompts. Emitted after every
   operator mutation via the `/api/schedules` surface (new /