docs: fix 329 Microsoft.Contractions hits with proper safety checks

Apply contraction fixes across ~40 doc files (setup, integrations, lifecycle,
networking, scheduler, swarm, tools, trust-boundary, UI, etc.). Skipped 14 hits:
- 10 where words appear in ALL CAPS for deliberate emphasis (is NOT, do NOT, etc.)
- 4 where text could not be safely located due to markdown formatting or column position

Applied via systematic scan with checks for fenced code blocks, inline code spans,
and intentional caps. Preserves sentence-initial capitalization throughout.

docs/web-ui/shape.md

@@ -225,7 +225,7 @@ returns inside the builder still commit whatever was appended
 before they returned.
 
 **Keyed DOM caching:** for sections whose rows hold interactive state
-(textarea drafts, checkboxes, focused inputs) `paintAtomic` is not
+(textarea drafts, checkboxes, focused inputs) `paintAtomic` isn't
 enough — wiping and rebuilding still destroys the state even if the
 flash is hidden. The keyed pattern keeps a `Map<id, {el, fingerprint}>`
 where the fingerprint is `JSON.stringify({...visible fields...})`.
@@ -234,7 +234,7 @@ textarea draft, checkbox state, and event listeners); only cache-miss
 rows are rebuilt and inserted. Used for: containers (`containerRowCache`),
 rebuild-queue entries (`rebuildQueueRowCache`). The spawn-form input+focus and meta-input
 checkboxes use a lighter snapshot-then-restore pattern (snapshot
-before `replaceChildren`, restore after) since they are single
+before `replaceChildren`, restore after) since they're single
 values rather than per-row caches.
 
 **`<details>` open-state preservation:** any collapsible element