docs: fix genuine Microsoft.Contractions/Negative errors

16 of the 23 error-level hits from a full-repo vale run were real:
'is/are/does/do NOT' and bold 'not' expanded per Microsoft.Contractions,
one hyphen-as-negative-number fixed to an en dash per Microsoft.Negative
(docs/web-ui/dashboard.md's -45 deg column-header tilt).

Where the caps/bold was there for emphasis (contrasting X does this,
Y does not), kept the emphasis by bolding the contraction rather than
dropping it silently -- 'is not' -> 'isn't', 'does NOT' -> '**doesn't**',
etc.

docs/tools/swarmctl-cli.md's one genuine hit is generated -- fixed the
source doc comment in swarmctl/src/main.rs and regenerated via
'cargo run --bin swarmctl -- markdown-docs', diffed against the old
copy first to confirm only the intended line changed.

Left 7 hits unfixed, false positives from the rule matching a
substring rather than the actual pattern it names:
- 4x 'that's instead of that is': every one is the explanatory 'that
  is' idiom (~= i.e.), not a contractible subject+verb -- 'that's'
  would misparse as a demonstrative-pronoun contraction and change the
  sentence's meaning. docs/integrations/forge.md:282,
  docs/tools/forge.md:260, docs/tools/hivectl.md:243,
  docs/web-ui/dashboard.md:457 (and the swarmctl-cli.md generated
  twin of the same category, source left alone for the same reason).
- docs/agent-lifecycle/persistence.md:482 -- 'is not' matched inside
  'is nothing' (the same has-not/has-nothing substring trap noted
  before in this doc's own git history).
- docs/swarm/ca.md:182 -- 'it is' matched inside the already-correct
  'it isn't'.

Per #4128. Remaining errors on main after this: Microsoft.Avoid's 26
hits, already tracked + awaiting a house-style ruling on #4041.

docs/web-ui/css-vars.md

@@ -73,7 +73,7 @@ default palette). Default hexes shown are Catppuccin Mocha.
 
 ## Common mistakes
 
-The Catppuccin colour names do **not** map 1:1 to the variable names.
+The Catppuccin colour names **don't** map 1:1 to the variable names.
 Variables to avoid (undefined — they will silently resolve to transparent / inherited):
 
 | Wrong                      | Correct                                             |

docs/web-ui/dashboard.md

@@ -99,8 +99,8 @@ messages are visible from any tab even while inactive. Backed by
 in_reply_to, file_refs).
 
 **◆ PR3F3R3NC3S ◆** — operator-local preferences. State lives in the
-browser's `localStorage` — preferences do NOT sync between devices and
-do NOT survive a profile wipe. One section today (browser
+browser's `localStorage` — preferences **don't** sync between devices and
+**don't** survive a profile wipe. One section today (browser
 notifications); future preferences land here as sibling `<h3>` blocks
 in `dashboard.html`. Was its own S3TT1NGS page/tile (`/settings.html`)
 until mara moved it in here — a standalone page for one toggle didn't
@@ -508,7 +508,7 @@ live container + any extra name that appears as a target on
 some schedule but isn't a current container (same
 `buildTargetChips` membership rule the new/edit forms use,
 so table and forms agree on what's addressable). Column
-headers tilt -45° via CSS so each column reads as a narrow
+headers tilt –45° via CSS so each column reads as a narrow
 ~28px strip; per-agent cells render as:
 
 - **active target** → `<button>✓</button>` that cancels just
@@ -614,7 +614,7 @@ the model id, longest match wins) mapping to
 `{ input, output, cache_read, cache_write }` USD-per-million-token
 prices. Models not covered fall back to hive-c0re's built-in estimate.
 
-The FL0W page does NOT host the PR3F3R3NC3S pane — it lives only on the
+The FL0W page **doesn't** host the PR3F3R3NC3S pane — it lives only on the
 dashboard's Y3R C4LL tab (reach it via the FL0W page's `← home`
 back-link → Dashboard). Notifications still fire on the FL0W page when
 they're enabled there, because `NOTIF.show()` in